Hey Erin! Both are made by Clearsnap, but chalk ink is considered a "hybrid", which is a kind of pigment ink/dye ink mix. They dry to a matte finish, and can be heat set to be permanent on most surfaces. I just happen to start out with Colorbox Chalk, and loved it so much I never got around to trying their pigment-only inks. You'll have to tell me how you like them.
Here's link to Clearsnap, and you can see their different inks:
https://www.clearsnap.com/blended-ink
and here's an article on chalk inks:
Scrapbooking.com -- Article - Chalk Ink Pads