Doesn't work. Seen this kind of design plenty of times. Creatures don't die to damage until state based actions are checked, so this spell will have finished resolving before anything has the chance to die

Possible alternative wording:

"Target creature you control fights another target creature. When one of the targeted creatures dies this turn, put two +1/+1 counters on the other creature."

That sets up a trigger to go off independent of the spell's resolution and state based effects. If both creatures die, then nothing happens. If two Wall of Woods have a Wild Brawl, and you Lightning Bolt one afterwards, then the remaining Wall of Wood will get two +1/+1 counters. It's not perfect. But few things in Magic are.

Big thanks :)

lol my bad haha

thanks for fixing it Frog