Does Volibear Legend's ability trigger when Sett enters play and gains Might from his own effect?

Ruling: No, Volibear Legend will not trigger from Sett's self-buff. Volibear Legend checks Sett's Might value at the moment Sett enters play, before Sett's triggered ability goes on the chain, so Sett will still only have 4 Might at that time.

Sequence:

• Sett enters play
• Volibear Legend checks if any unit has 5+ Might (Sett has 4 at this point)
• Volibear Legend does not trigger
• Sett's triggered ability goes on the chain
• Sett's ability resolves and grants him +1 Might (now at 5)
• The trigger window for Volibear Legend has already passed

Nuances:

• Draven Showboat will trigger Volibear Legend because his effect doesn't use the chain and applies immediately, so the Might increase happens before the trigger check