Some of them are still green on the bit of the leaf still attached to the tuber and some are all brown. Are the brown ones worth planting?
I suspect you were given rhizomes from a very overgrown neglected iris bed. You will only want to plant those that have fleshy roots. If the roots are all shriveled and flat and completely dried out, or even gone (non existent), just pitch those

If I am not going to plant them in the ground soon, should I plant them into soil in nursery pots and keep them watered until I have the ground ready to plant them in or just leave them in the bag?
I would probably skip the potting them up and just keep them shaded and dry until you have a 'large' area prepped for them.

Please see How do I dig, divide, and transplant bearded irises? one of the FAQ here at the forum. It tells how to plant as well as how to space your rhizome so they won't be too crowded too soon.

Have fun!

Sue...chemocurl

Do you know if they are all the same color?

If they aren't, you can also plant the ones with brown leaves as there may be babies that will emerge from the mother rhizome.