I have strung several MM basses BEAD, mostly StingRays. They actually take it quite well, better than almost any other axe, IMO. I always have at least two that way for one of my bands (about 30 gigs per year).
You DO NOT need to get a new nut blank. In the 10-12 times I've done it, over several bass manufacturers and models, I've never replaced a nut to switch to BEAD - or back to EADG.
You can do this if you very carefully widen the slots. In fact, you rarely need to widen anything other than the 4th string slot. The other 3, in my experience, will fit the larger strings fine most of the time. If you don't want to buy a real nut file, take the new string and use it as your file by gently rubbing it back and forth on the slot (stop giggling, Beavis!). Just keep it square to the nut, and don't dig in too deep. Stop when the string sits in the bottom of the slot.
You will need to re-set-up the bass to accommodate the different tensions. In fact, I generally do a small adjustment, then wait 24 hours because the bass will settle in.
When you go back to EADG, you should be able to switch strings and re-set the bass without changing out the nut.
EDIT: One more thing. Try different strings to find a tension you like. I HATE floppy B strings, and generally like Ken Smith Rock Masters with a tapered B @ .130 for my MMs that are BEAD. I really dislike DDTs, there's a whole thread here about that love/hate thing.
Good luck!