These are two different old chips with "MIAN" on them, same both sides.
I can't find any listing or attribution for MAIN anywhere, but there is a chip from the "MAIN TAP" in Havana, Illinois that has the same font in the word "MAIN" (R) but with (tap) as well.
I will include a pic from Hertel’s 4th edition guide to show both MAIN TAP chips he lists. Anyone have any info or comments? They look like the same font but that doesn't mean much. I will sell the pair of chips for $30 shipped. paypal only, email please...