Is X-37B some kind of nuclear bomber?

The space shuttle is a modular system. It is always suitable for military and civil missions. 

GLSDB (Ground-Lauch Small Diameter Bomb) type systems can give missiles pinpoint accuracy even in intercontinental range. AI-based optical seekers can make it possible that small-diameter bombs can destroy individual vehicles or other targets in extremely long-range. And the same weapon used in GLSDB can install even in intercontinental boosters like Minuteman or Trident missiles. 

Dream Chaser

X-37B

X-37B is a miniature shuttle. That space system has a cargo room, like larger shuttles. But the size of X-37B and its successors like "Dream Chaser" is far smaller than well-known big shuttles. But that cargo bays make all space shuttles multi-use tools. 

There is the possibility that small telescopes and other kinds of observation systems are put in those small and highly secretive shuttles. There is the possibility that the X-37B type of shuttle can raise remote-controlled biological or nanotechnical research laboratories to a non-gravitational environment. 

And then those laboratories can return to Earth in those cargo bays. The fact is that. X-37B can also carry nuclear weapons in its cargo bay. The space bombers would not necessarily use nuclear weapons.

The miniature shuttles also can serve as space fighters in ASAT missions. But they also can bomb targets on the ground. For those missions, the space bomber requires a bomb with normal bombs with heat shields. 

This type of shuttle can make kamikaze missions against targets, or it can drop those nuclear bombs through the atmosphere. When people talk about things like fractional orbital bombardment systems. They forget one thing. FOBS (Fractional Orbital Bombardment Systems) weapon or orbital bombardment weapon is not always a big one.

 In some visions, the military can put 280 mm. nuclear grenades in small-size satellites and drop them on targets. The U.S. military tested that nuclear grenade in the nuclear test "Upshot-Knothole Grable".  Another thing is that the FOBS systems don't need to use nuclear warheads. The orbital bombardment systems can also drop conventional weapons like smart glide bombs from satellites. 

Those glide bombs or smart weapons are similar to GLSDB (Ground Launched Small Diameter Bombs. But their rocket is much more powerful. That means, GLSDB can just put to the nose of the Minuteman missile. 

Glide bombs,  used in long-range missiles are not necessarily hypersonic. Hypersonic technology is fascinating. But there is the possibility that those glide bombs are like normal spacecraft that have a heat shield and inertia- and smart optical or image homing system. The weapon flies to the target by using inertia. And in terminal sequence, that kind of weapon can turn to use an optical homing system. 

And also things like conventional glide bombs with advanced optical seekers can shoot to target areas by using ballistic missiles. The GLSDB (Ground Launched Small Diameter Bomb) can also mount in long-range missiles. There is a possibility that the Israeli "Spice" intelligent stand-off weapons can install also in a long-range missile. The intelligent image-homing. Used in Javelin-missiles can give those glide bombs ultimate accuracy. 

The glide bomb can be a small-size space shuttle that has wings. The thing is that a glide bomb that is launched through ballistic- or orbital trajectories is not necessarily hypersonic. They can be stealth technology using supersonic systems that are conventional weapons.