Yes, just put them in a freezer bag and squeeze out plenty of air from it before you tie it up. It doesn't matter if they're shelled/crushed etc. You can keep them for as long as anything else - some say 6 months, some say a year, some say indefinitely.
We always freeze our pecans and raw peanuts. I was shelling pecans tonight that I put in the freezer 14 years ago. this is December 2018, No problem with flavor or color. Sounds crazy but they will last indefinitely. Bud H.