Repo steps:
# Go to Edit > Project settings > Tags and Layers
# Click the drop down arrow in Sorting Layers
# Click the Plus button to add a new layer
# Observe Console

Expected Result: No errors in console

Actual Result: Error in the console 

Reproducible with:  2022.2.9f1, 2022.2.11f1, 2023.1.0b8, 2023.2.0a6.

Not Reproducible with: 2022.2.8f1, 2021.3.20f1, 2020.3.46f1.

Platforms tested: Win 11, MacOS Monterey, Version 12.6.2 

Notes: 

NullReferenceException: Object reference not set to an instance of an object

UnityEditor.TagManagerInspector.AddToSortLayerList (UnityEditorInternal.ReorderableList list) (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditorInternal.ReorderableList+Defaults.DrawFooter (UnityEngine.Rect rect, UnityEditorInternal.ReorderableList list) (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditorInternal.ReorderableList.DoListFooter (UnityEngine.Rect footerRect) (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditorInternal.ReorderableList.DoLayoutList () (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditor.TagManagerInspector.OnInspectorGUI () (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditor.AssetSettingsProvider.OnGUI (System.String searchContext) (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditor.SettingsWindow.DrawControls () (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEditor.SettingsWindow.DrawSettingsPanel () (at <335b34ef534e437c860b1c21cb87dc9c>:0)

UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, UnityEngine.Matrix4x4 worldTransform, UnityEngine.Rect clippingRect, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Boolean canAffectFocus) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUIRaw (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUI (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.ProcessEvent (UnityEngine.UIElements.EventBase evt) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.IMGUIContainer.ExecuteDefaultActionAtTarget (UnityEngine.UIElements.EventBase evt) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatchUtilities.HandleEvent_DefaultActionAtTarget (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel, UnityEngine.UIElements.VisualElement target) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatchUtilities.DispatchToCapturingElement (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel, System.Int32 pointerId, UnityEngine.Vector2 position) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatchUtilities.DispatchToCapturingElementOrElementUnderPointer (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel, System.Int32 pointerId, UnityEngine.Vector2 position) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.MouseEventBase`1[T].Dispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcher.ProcessEventQueue () (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcher.OpenGate () (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcherGate.Dispose () (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& eventHandled) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.UIEventRegistration.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.UIElements.UIEventRegistration+<>c.<.cctor>b__1_2 (System.Int32 i, System.IntPtr ptr) (at <bbc67888babf4b1bb902e41b96b884a0>:0)

UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& result) (at <5c4beea130f443f7af2be835cb11f79f>:0)