And what Israeli bombers can fly 1,000 miles loaded with bombs and return that same 1,000 miles without refueling?
Israel has seven Boeing 707 tankers and three Lockheed C-130 tankers, both with multi-thousand-mile ranges, so they wouldn't need to do it withuot refueling. However, bombers generally don't do that anyway, since they're normally big long-range planes themselves, like cargo planes and high-capacity commercial passenger planes.
I'm not sure what kind of plane would carry the nukes because they don't seem to have a dedicated bomber, but I figure they'd probably use one of their "transport" planes with a bit of modification. They have 26 of those, including seventeen C-130s, six 707s, and three Gulfstream G550s, all with plenty of range for this without even refueling. (They also have nine Aravas but those have shorter ranges and would need to refuel; their advantage is short take-off, which doesn't matter in this case.) Nukes are rather large and heavy (the "suitcase" type being a myth), so fighters can't carry them (and if they could then it would limit how much other stuff they could carry, such as fuel and other weapons), and fighters have shorter ranges and would thus need refueling along the way there or back. Of course, if you send bombers/transports, they'll need fighter escort for protection anyway, but you're better off arming those fighters with conventional air-to-air weapons.
Israel has 97 Eagles, 345 Falcons, and 50 Phantoms (total 492). Iran has 20 Tomcats, 4 of which are thought to still be flyable, and 24 French Mirages, 42 Chinese J-6s & J-7s, about 10 to a couple dozen homemade HESA fighters, 44 Phantoms, 40 MiG-29s, 75 Tigers, and 3-10 Russian Sukhoi-25s (total at least 242, in the 280s at most). Refuel Israel's fighters in flight or let them use an American airfield that's closer on the way there or back or both (in Iraq, Kuwait, or maybe Qatar), and it's no contest, in either numbers or the quality of the planes, even leaving some behind to prevent other local crazies from trying to take advantage of the situation. They'd certainly get through and hit their targets and mostly get back. The question is how many losses they'd have while they were at it. I'd guess in the dozens, maybe even close to a hundred, if Iran's pilots fought to the very last one.
If Israel wanted to use nukes, it would be simpler, cheaper, quicker, and safer to launch them on Jericho II or Jericho III ballistic missiles. These can't reach all the way around the planet, but they can more than cover Iran. There could be some risk of having the missiles shot down before they hit their targets, but Iran probably can't do that.
Of course, Israel wouldn't need to use nukes to strike certain targets in Iran, and their recent exercises are probably intended to prepare for non-nuclear missions aimed at Iran's own nukes. That means actually going to a lot of trouble and sacrifice to AVOID using their own nukes even when it would be simpler, cheaper, quicker, and safer for them.
