The Church of Jesus Christ of Latter-day Saints teach self defense is fine.

From [Doctrine & Covenants Teacher's Manual][1]

>As peaceful, law-abiding citizens, Latter-day Saints renounce war and proclaim the gospel of peace but will stand unto death in defense of their God-given liberties.

Under [Children & Youth Development: Goals and Activities][2]:

>Learning self-defense can help you feel safe. **You will also have a better idea of what to do if there’s a threat to yourself or someone else**, whether you’re at school, in your neighborhood, or anyplace else.

And [Is Fighting Ever Ok][3]
>However, the Lord also spoke of self-defense: “Nevertheless, thine enemy is in thine hands; and if thou rewardest him according to his works thou art justified; if he has sought thy life, and thy life is endangered by him, thine enemy is in thine hands and thou art justified” (Doctrine and Covenants 98:31).

See also:
- [Scripture References to Defense][4]

With that said I don't/haven't necessarily seen this as a common teaching with sacrament talks, general conference addresses, or sunday school lessons.

Well known Book of Mormon example to support self defense would be the [Title of Liberty][5] ([Alma 46:12-13][6])

>A banner raised by Moroni, chief commander of the Nephite armies in the Book of Mormon. Moroni made the banner to inspire the Nephite people to defend their religion, freedom, peace, and families.

<sub>emphasis mine</sub>


  [1]: https://www.churchofjesuschrist.org/study/manual/doctrine-and-covenants-instructors-guide-religion-324-325/renounce-war-proclaim-the-gospel-of-peace-lesson-39-sections-98-99-106-108?lang=eng
  [2]: https://www.churchofjesuschrist.org/study/test/dive/goals-activities/learn-self-defense?lang=eng
  [3]: https://www.churchofjesuschrist.org/inspiration/is-fighting-ever-ok?lang=eng
  [4]: https://www.churchofjesuschrist.org/study/scriptures/triple-index/defence?lang=eng
  [5]: https://www.churchofjesuschrist.org/study/scriptures/gs/title-of-liberty?lang=eng
  [6]: https://www.churchofjesuschrist.org/study/scriptures/bofm/alma/46?lang=eng&id=12-13#p12