How can I beat my X Nuzlocke with only Squirtle remaining?

Question

I have beaten the cyllage city gym with one Pokemon remaining a level thirty squirtle. I have no extra Pokemon in the PC. They are all dead. Already caught Pokemon on the way to geosenge town before battling the gym leader. I also already fished in the water near cyllage city before the gym battle.

Answer 1

I'd just level up a lot and then you'd probably be fine