U can play KIA vs virtually everything. Generally speaking, Nf3 + g3 is already KIA.
Different ways to reach Kings Indian Attack.

Yeah the KIA is its own opening. Some people set out to play it from the start with 1.Nf3. I use it as part of my e4 repertoire. I play it against the French and 2...e6 Sicilians. It's also used against the caro kann but I don't like it against that as much.
... Generally speaking, Nf3 + g3 is already KIA.
Seirawan suggested this sort of thing for White in his 1999 book, Winning Chess Openings,
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
and he used the overall name, Barcza Opening, adding that the King's Indian Attack was one possible direction for the subsequent moves.
I recently found out that i really enjoy playing this opening, and is useful to get players away from the main line..
What i want to know are the different ways to reach this position.
The ones i know are:
1. French defence: e4 e6 d6 d5 nbd2
2. Sicilian : e4 c5 nf3 e6 d3 d5
Any other ways to reach it?