There are lots of waterfalls in the area, there's one in Palo María, a few upriver from Mismaloya, El Edén being an accessible option. There's a nice one at Las Juntas and Los Veranos, on the southern beaches, there's a nice one at Quimixto (see below) and in Yelapa.
Waterfall in Quimixto
Waterfall at El Eden
Some Puerto Vallarta Waterfall videos on Youtube: