I've been asked about chip board. I have to admit I've heard of chip board but I don't think I have ever had any. I use mat board because it's 1/16 inch thick, if your chip board is 1/16 inch thick and it glues I would go ahead a use it. Will it sand? Will it take paint? If so, use it. I use what I have around the house for substitution. I think one of the great things about miniatures is that you use what you can find, it's all about substitution, if it works for you, use it.
Mat board is what is used to mat pictures with when they are framed, it's found in the framing department of Michael's or at a picture framer's. It comes in lots and lots of colors. You can also choose between white and cream for the inside color. That's for when the mat board is cut at an angle, you can see the inside contrasted with the surface color.