Op here. I did end up getting a foil roasting pan today. I was just curious if I could use the dutch oven since I feel like I don't use it enough. Thanks for the replies.

How about getting a foil roasting pan at the supermarket?

the sides might be too high for it to brown properly. it might work if you put it on a bed of carrots/celery etc.

I've cooked this recipe b/f, which calls for a baking sheet:
http://www.pbs.org/everydayfood/recipes/mustard_crusted_turkey.html

One thing though, I'm not sure why but just the breast rendered quite a bit of fat and it got a little smokey, so make sure your exhaust fan is working and put an empty sheet pan underneath in case anything drips.

the next time I make it, I was thinking I might try a broiler pan vs. a sheet pan

Absolutely. I use the same method (or my iron skillet) to roast chickens all the time.

Just making a turkey breast on Thursday and don't have a good roasting pan. Can I cook it in a dutch oven with the lid off?