Seismitoad all the way, my friend. Not only is Palpitoad ugly as a monkey's armpit, but but its offensive stats are deplorable. A little more bulk won't mean anything if you aren't KOing your opponents, and as you progress later in the game Palpitoad will struggle to do just that. The Eviolite boost isn't worth it, in my opinion, because Seisitoad's 105/75/75 bulk coupled with only one weakness is more than adequate in-game, especially if you're a few levels higher than your opponent. On top of all that, by not evolving it you miss out on learning Drain Punch, a move with decent power and coverage that will also heal Seismitoad.
If you're looking for a moveset, this one should perform pretty well:
[email protected] Big Root (for Drain Punch) or any item you see fit
- Mud Shot / Dig
- Drain Punch / Poison Jab
Surf is self-explanatory. Scald is for when you're in a double or triple battle and don't want to drown your allies, plus getting burns on tough enemies like N's Bouffalant can be a lifesaver (you may laugh, but that freaky afro buffalo has swept me twice). Mud Shot and Dig are for Ground STAB. Dig is all-around better, but until you get it Mud Shot isn't terrible. Earthquake isn't available until the postgame. Finally, either Drain Punch or Poison Jab for coverage — but I strongly recommend Drain Punch to deal with tougher foes like Hydreigon and Bouffalant.
Some possible nicknames are Julius Seisar, Toad Truck, Pimples, or Kermit.
I hope this helps!