The following are known Action Replay Codes for Mega Man: Battle Chip Challenge on Nintendo Game Boy Advance (GBA).
These codes were also known as GameShark Codes and in most cases will work on both devices.

These codes are for the U.S. version of the game.

Master Code – Must Be On
ca54c605
6e90a777
4e3e0389
73f530f7

Infinite Zenny
1d4f0290
9cc33b9f

Infinite HP
d416722d
05020010

1 Hit Kills Enemies
95bf70a2
f31071ce
48109b8a
614ade2b

Have All Chips in Backpack
09ec50c5
77155772
34184998
8c3a463a
5c0cacca
8cb750c7
ef4dc89c
0a8473b4