There are two things to do in this mission, simultaneously. One is to kill N.O.X and the other is to rapidly wipe out the increasing spawns of Bit Golems which increase N.O.X's power. The party will quickly be overwhelmed if these are allowed to build up. Use of interrupts and dazed condition help here. Alternatively, keeping Protective Spirit on N.O.X.'s target will eliminate all of the extra damage the Bits add to N.O.X.'s attacks, allowing the party to completely ignore them. Pain Inverter can be used to turn the high damage N.O.X. puts out against itself; in that case, don't bother to kill the bit golems. The Sunspear skill Intensity can be used to raise the damage further. An alternative strategy for a DPS class is to bring at least a ranger with Broad Head Arrow and high Marksmanship