Remember, in NiGHTS into Dreams: An Ideya Capture has 20 HP. To Kill an Ideya Capture (and Free the Ideya), You must have Twenty NiGHTS Chips (if the Capture is Not Damaged) or the Number of NiGHTS Chips equal to the Ideya Capture's HP (if the Capture is Damaged).
According to the Math: 1 NiGHTS Chip = 1 Damage to the Ideya Capture.