It used to be viable, but now that Tapu Koko is here, it's not good thanks to it's low speed. Pincurchin would have been good to use with Alolan Raichu, because of Pincurchin's hidden ability Electric Surge, which would activate Raichu's ability Surge Surfer, which doubles speed on Electric Terrain. But now Tapu Koko can set up Electric Terrain with the same ability and partner with Regieleki. Regieleki + Electric Terrain + Transistor (Regieleki's ability) + Raising Voltage = MASSIVE DAMAGE!
All in all, Tapu Koko is waaaaaaaaaaaaaaaay better.
Hope I helped!