Anxiety can usually cause one to create habits to cope that can be problematic. Perhaps addressing anxiety and helping you find triggers will be helpful. Trying an antidepressant such as luvox, zoloft could help reduce the emotional distress that may drive you to bite your nails combined with cognitive behavioral therapy.

You can wear gloves and keep your hand busy with another thing.

See a therapist to learn where this coping mechanism is coming from and why.

Onychophagia (severe chronic nail biting) is common & is sometimes felt to be due to OCD or anxiety disorders. Most now suspect a neurologic origin, Initially several counter maneuvers are recommended. If this fails there is Avery bitter nail polish that often subconsciously ameliorates the behavior. (Denatonium benzoate). Currently new technologies are allowing neuroscience to delineate the origins. Lately particular antidepressants have been found to be effective. There is a subspecialty of Neurology that is beginning to look at this and a Movement Disorder sub specialist in Neurology should have some good ideas. Best of luck. It is a frustrating condition but future resolution of the condition for most is near. Best of luck.

See if this link is useful:

https://www.healthline.com/health/how-to-stop-biting-your-nails

Put something on your finger nails that are not tasty. Try to stop your self every time you catch yourself doing so