NSMB has a 4.1 update.
EO2 has a 4.2 update. Updating to 4.2 will remove your modchips region features, removing your ability to play any NTSC game, unless you softmod.
You can safely update using NSMB to bring your Wii to 4.1 and get new IOS but you should avoid the EO2 update if you can.
Enter your Wiikey settings after the NSMB update and disable all updates and see if you can load the game. If you cannot then you'll need to softmod or lose your ability to load NTSC games.