If Viktor, Leader and another non-token Unit you control die in Combat at the same time, does Viktor's ability trigger?

Ruling: No, Viktor does not trigger. Viktor needs to still be on the board for his ability to trigger, and triggered abilities of permanents can only have their conditions evaluated while on the Board.

Nuances:

• This applies even though the other Unit dies at the same time as Viktor
• Viktor cannot "see" the other Unit die because he is not on the board when the trigger condition would be evaluated