Merriam-Webster online had to make a note of it. And it is because there's enough people saying it this way as well.
Though disapproved of by many, pronunciations ending in \-ky&-l&r\ have been found in widespread use among educated speakers including scientists, lawyers, professors, congressmen, U.S. cabinet members, and at least one U.S. president and one vice president. While most common in the U.S., these pronunciations have also been heard from British and Canadian speakers.
It's not a crime but it tends to make me blink each time I hear it. Is it a tongue twister or just playing along with the pack you run with? Don't want to be the oddball who'll insist on saying "nu-klee-yer," my friends will think I'm not down with them. Or sumpin'. It's the same reaction I have to hearing people say "ax" when they mean to "ask" something.
I usually chide my kids to go look it up in the dictionary when they hear me go off on this tirade about "nukular." Now they can point to how even the dictionary had to acknowlege that people say it the way I say not to.
Link to Merriam Webster online entry on nuclear
Link to Slate article