The first ability on Chandra is both zero and plus one, since it puts the counter on itself. This means that you don't need to play Acolyte of Flame with other red planeswalkers for it to be useful.
The second ability is a nice way to push damage without spending any loyalty counters. So think of it as a free bonus, which can be really useful on an empty board.
The minus two ability is where things get really spicy. It's basically a Snapcaster Mage ability, which can be activated twice in a row or more if you can wait a turn here and there.
All in all, this is a very effective planeswalker that costs only three mana, and serves well in almost every red deck.