I'm trying to think but there aren't a lot of sci-fi shows with a nuclear family period, are there?
Not many, but there are more than just one or two. Off the top of my head:
Lost in Space -- the nuclear Robinson family, all white, of course -- a given
The 100 -- several families of mixed races, mostly dysfunctional
Terra Nova -- didn't watch but includes the Shannon family I believe
Earth 2 -- also didn't watch -- seems to be a mix of two single-parent families and a couple without children -- probably doesn't count
Stranger Things
The Jetsons -- probably nuclear in more than one sense
ALF
Metal Mickey -- obscure outside the UK
Space Precinct -- the Brogan family
3rd Rock from the Sun -- maybe, maybe not
ETA a few more:
The Martian Chronicles -- the Wilders in episode 3 "The Martians" are a nuclear family and Earth gets nuked
Goodnight Sweetheart -- time-travelling bigamist from the 90s goes back to the 40s and starts a family
Dune -- Duke Leto, Jessica and Paul Atreides nearly count a nuclear family, apart from the parents not being married and actual nukes are forbidden, of course
Bicentennial Man -- the Martin family -- however, a movie rather than a show