Sure you can, it's your quilt. I've been thinking of making one myself, but there are things to consider. The knit can stretch, so it may have to be backed with a fusible stabilizer, like when making T-shirt quilts. Also, I hear it can be quite heavy, so just a backing, without a batting, would probably be best. I wouldn't mix knit with regular cotton in the quilt, but I would think you could still use cotton for the backing, since the knit would be stabilized. I don't know. Hopefully, someone with more experience can give us some more insight into this.