Look errm, Pichu is a really bad Pokemon to use in LC due to it's horrid stats. The only half decent stat is speed but if you really want to use it;
Pichu @ Life Orb
EVs: 36 HP / 236 SpA / 196 Spe
Thunderbolt is for STAB, HP Grass for coverage. With pichu's good speed, encore is probably your best bet for a setup since pichu's defenses are so subpar, and nasty plot is the boosting move.
You could run a choice band set with volt tackle/return/thunderpunch/iron tail but Volt Tackle, Pichu's strongest move has alot of recoil so Pichu isn't going to stay alive for long. =/