Could they do the job and/or train others? It's possible; however have you any idea what it takes to move that stuff around the world and keep it viable, WHILST HIDDEN? It's a job that takes our military vast amounts of skilled and well trained men to do.
The lower echelons are now doing the "dirty deeds". Look at the recent events in London. From the idiot "shoe bomber" on down, these aren't people with enough skill to smuggle 12 to 70 ( THIS NEEDS A GIGANTIC QUANTY OF TINFOIL TO SWALLOW! ) nuke into America and then set them all off at once.
But heck, anything is "possible"...but probable? ROTFLOL