Well, you can certainly orbit a satellite without being able to build an ICBM. However, your question is difficult to answer without knowing two
1) How much does this satellite of Iran's weigh?
2) How much will Iran's 1st generation nukes weigh?
Iran has never tested anything more capable than a Medium-Range Ballistic Missile (MRBM), the Shahab
; Iran is pretty secretive about their missile program, but Astronautix and
agree that the Shahab 3 can loft at least 1500 lbs. about 1,200 miles.
Equipped with some sort of upper stage(s) the Shahab 3 would probably be capable of orbiting a satellite weighing a few hundred pounds.
The problem is that nukes tend to be heavy, especially early generation examples. The
bomb that was used against Hiroshima weighed in at 8900 lbs. That's
nearly six times the Shahab 3's estimated throw weight to 1200 miles - which is less than half the distance required to be considered an ICBM. A
missile isn't an ICBM until has a range of at least 5500 km (3500 miles)
. As far as we
know Iran doesn't have anything of that caliber, at least not yet.
Iran isn't likely to be able to build (relatively) light nuclear weapons anytime soon - even the US's
W87 nuclear warhead
, the newest in the U.S. arsenal (that we know of), probably weighs
in at ~800 lbs, if you include the re-entry vehicle. Iran's first nukes aren't going to be nearly that light. Iran has never, to the best of my
knowledge, flown a missile with more than one thrust chamber, has never successfully flow a multi-stage missile, has not (yet) successfully tested a
nuclear weapon, and has no experience building a re-entry vehicle for an ICBM-bourne nuclear warhead.
Additionally, Iran has no experience building a nuclear warhead able to tolerate the G-forces experienced during an ICBM launch. The fairly delicate
electronic components of early U.S. and Soviet nukes - in addition to their great weight - is one reason they were designed to be dropped from bombers
and not deployed on missiles.
Iran has been talking about launching a satellite for years, and will probably do so in fairly short order. However, I do not - for all the reasons
listed above - see Iran building a true nuclear-armed ICBM soon (i.e. the next 5 years). I'm sure they'd like to - and they're undoubtably moving
in that direction - but they're not there yet.
Of course that's all just best-guess data and my opinion.