Using HIPS as support for PLA printing?
You can as PLA is not affected by Limonene (the chemical used to dissolve the HIPS) but it is not recommended as the print temperatures for each material (~180C for PLA and ~230C for HIPS) are quite far apart and the PLA may not stick to the HIPS.

A better choice would be PVA which prints ~185C and dissolves in water but this material has its own set of fun issues.

*Temperatures are estimates, different vendors may have different temperatures.