The following are known Action Replay Codes for N2O: Nitrous Oxide on Sony Playstation (PS1).

The codes should work with the region specified but may work for other regions as well.

Device Compatibility: Action Replay, CodeBreaker & GameShark

Infinite Lives P1
8011b3540103

Infinite Lives P2
8011b36c0103

Infinite Shields P1
8011b1fc1117

Infinite Shields P2
8011b27c0ffa

Inf Sp Ammo & Firewalls P1
8011b2120a63
8011b2930a63

Driller Counter
8011b4880e60