I've never made it, but out of curiosity, did you include the adobo sauce as well in that 3/4 cup of minced chipotles the recipe calls for? The sauce itself has a bit of a kick, over the chipotles themselves.
3/4 of a cup is, near as makes no difference in a recipe this size, a smidge less than the contents of a 7oz can. So if it were me (and since this is being used as a glaze), I'd pour the whole can in the saucepan along with all the other ingredients and blitz the shit out of it with a stick blender, vs standing there and mincing those messy and slippery chipotles. It'll save time on mincing the garlic, as well.
If I didn't own a stick blender (saves dishes ya know), I'd pulse it all in a food processor. And if I didn't own a food processor, I'd pulse it in a blender.
Try that next time you make it, before changing anything else.