You CAN'T use two different size nozzles in the same print!

No, there no way to assign individual nozzles to object in slicer right now.

What I think they can integrate very easily is different nozzle sizes for different layers. So you can use 0.2 for first couple of layers for markings/text and 0.4/0.6 for all other layers. I hope that comes sooner than later.

I started a feature request for this, please like the post if you want this feature: