Distilled water can be used in a Keurig coffee maker but it's not recommended because it can make the coffee taste a little weird and give the coffee a metallic taste.
I tried it myself using distilled water and the coffee turned out nasty but if you like the taste of metallic coffee then using distilled water would be okay.
Distilled water can also clog up the keurig coffee maker as well due to the hardness of the distilled water.
I just use regular tap water for my Keurig coffee maker machine and have had no issues with it but if you prefer you can use some bottled water that is not distilled.
Distilled water also lacks the needed mineral content that filtered water has and will make for a flatter tasting coffee when used in the Keurig coffee machine or other coffee makers.