Reality and Battletech go hand in hand like a drug induced hallucination and engineering a fusion reactor ;-)
The nanites could be powered wirelessly by the fusion reactor, should have a lot of power for that. Maybe even use bricks/blocks or pellets of armor and the nanites only fuse them together at the right place.
There are two problems with powering nanites, the first is getting the power to the nanite and the second is not destroying nanites with the power. The amount of energy needed to blow apart a nanite is measured in electron volts. Wireless power transmission has the fun limitation that the amount of energy taken up by the receiver is proportional to the area of the receiver. For nanites, this is on the order of 10^-16 square meters, so you can do the math on the energy density of the field. A nasty effect is that it will take potentials of a few millivolts to electrically power a nanite and they are only tens of nanometers long, so the electrical field strength will be tens of millions of volts per meter, a stress that no insulator, not even a hard vacuum, will support.
A big problem for nanite armor repair is that the damage is almost always on the outside, and even anthrax can only endure battlefield conditions as a dormant spore. If nanites cannot repair armor during a fight, they must be compared to a tech who is much faster, can handle blocks that are much more massive, and is much better at identifying battle damage.
K-F drives don't work by generating wormholes. StratOps says that very bluntly. The ComStar sourcebook indicates HPGs work by the same basic hyperspace mechanics as K-F drives, so this is a non-starter.
I did say "If". However, unless K-F drives and HPG's do not warp space, at all (outside of warping space from their mass), the physical possibility exists for anti-gravity, even if the engineering problems are insurmountable. The one hope that we (you, me, and everyone else in real life) have for FTL travel is that while no easy mechanism suggests itself to accomplish that goal, General Relativity does not absolutely forbid it. If we happen to live in an eight dimensional universe and can produce negative matter (bizarre stuff that is repelled by gravity), FTL, anti-gravity, and time travel become real, as opposed to hypothetical, possibilities (there are no shortage of physicists laboring to modify GR to make time travel absolutely impossible, but they have yet to succeed).