Nazar, the Velvet Fang

• WOTC Official Reminder Textofficial rules
  Menace — This creature can't be blocked except by two or more creatures.

• WWizards of the Coast2024-11-08
  Official Ruling
  If you gain an amount of life "for each" of something or "equal to the number" of something, that life is gained as one event and Nazar's second ability triggers only once.
• WWizards of the Coast2024-11-08
  Official Ruling
  Each creature with lifelink dealing combat damage causes a separate life-gaining event. For example, if two creatures you control with lifelink deal combat damage at the same time, Nazar's second ability will trigger twice. However, if a single creature you control with lifelink deals combat damage to multiple creatures, players, planeswalkers, and/or battles at the same time (perhaps because it has trample or was blocked by more than one creature), the ability will trigger only once.
• WWizards of the Coast2024-11-08
  Official Ruling
  In a Two-Headed Giant game, life gained by your teammate won't cause Nazar's second ability to trigger, even though it caused your team's life total to increase.
• WWizards of the Coast2024-11-08
  Official Ruling
  Nazar's second ability triggers just once for each life-gaining event, whether it's 1 life from Dazzling Angel or 4 life from Apothecary Stomper.
• WWizards of the Coast2024-11-08
  Official Ruling
  If Nazar isn't on the battlefield as its last ability resolves, you can't remove three feeding counters from it, even if it had three or more feeding counters on it before it left the battlefield. You won't draw cards or lose life.

Rulings via Scryfall