Fixing a creaking NEW chipboard floor
I'm not sure what's available in your area, but heavy duty construction adhesive is ideal for this. I've resolved many annoying squeaks and pops by running beads along all accessible joints, then fingering it out to spread it and press it into the gaps. (Use disposable gloves or a tool to prevent a lasting bond to skin.) Over a few days it hardens nicely and bonds extremely well. 

In addition, add construction screws where you can to tighten joints and prevent slippage of existing fasteners.