That's water injection. Air/Water intercooler hasn't been banned anywhere I've been this year.
The only place NADM rules mention an intercooler/aftercooler is in the ballast section:
"The ballast box must be securely fastened to the frame or cross
member with at least two 1/2 inch diameter steel bolts. Any liquid
other than consumable engine fuel that is located behind the front
firewall (on a front-engine
vehicle), is considered ballast and is prohibited, except for intercooler
tanks that contain water and/or ice only. The tank must be securely
mounted to frame, frame member, or OEM floor pan."