Kind of an odd question here.
First let's define what an "average" nuclear explosion is, because that's quite a controversial term - "average". Considering that the peak of nuclear tests was at the 1960s, and that the bulk of nuclear or thermonuclear devices developed in that period were fission bombs, and disregarding radical developments like the Tsar Bomba or the B41 nuclear bomb, I'd say it's safe to proclaim an explosion yielding ~800t of TNT is average on these terms.
To back up my numbers I cite the statistics for 60s-era nuclear tests, like Operation Nougat, Operation Dominic, Operation Whetstone, Operation Latchkey and Operation Flintlock. The numbers are readily available on Wikipedia.
Now to the Space Shuttle.
The solid rocket boosters (SRBs) of a Space Shuttle exert 14MN (14x10^6 Newtons) of thrust each shortly after liftoff, and provide 80% of thrust for the whole stack until they are jettisoned at 46km above sea level. Their thrust level is constant until the fuel is burnt and depleted.
The SSMEs (Space Shuttle Main Engines each produce ~2MN of thrust at 100% throttle up until the Shuttle reaches orbit at 320km altitude.
Considering that work can be measured in Newtons per meters, ie., J = Nm, therefore:
14x10^6N * 46,000m = 644x10^9J
x 2 SRBs = 1,288x10^9J
2x10^6N * 320,000m = 640x10^9J
x 3 SSMEs = 1,920x10^9J
SSMEs + SRBs = 3,208x10^9J or 3.2x10^12J or 3.2TJ.
1kt of TNT equals 4.184TJ, therefore, one Space Shuttle launch is equal to around 760 tons of TNT across the whole 320km stretch.
Did I get the work/energy/force relationships right?