The limit is sixteen patterns, but the pattern length can be one bar, or four bars, or whatever length. Changing the step rate to increase the actual number of bars the pattern runs for can increase the total time for the chain, though does mean "lively" melodies will not be so "lively".
I've chained up patterns with step counts that are odd numbers for each sequencer and made some very messy polyrhythms. That is where noting down more than just the pattern number is helpful. I've even thought about making up a chain grid to mark out where everything is going to fall and create some nice interactions with the pattern being different lengths before hitting play.