Using HIPS as support for PLA printing? I have a question. I have a dual extruder printer and I want to try using HIPS for printing. Can I use PLA as my main material and HIPS for supports?

Searching online I found combinations of ABS + HIPS mentioned. No where is it mentioned that It can be used.
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.