If we excite them to states above their decay threshold, sure. We do this all the time.
ETA: That was a bit terse. Sorry. The reason nuclei decay is because it is energetically favourable for them to do so - the product is more stable. Like atoms, nuclei have excited states, governed by quantum mechanics. If you promote the nucleus from the ground to excited states through a reaction, there will be a point after which it becomes unstable to decay.
An example is 6Li (chosen because I have the level scheme open, no particular reason). The ground state is stable, but if you promote it to the first excited state at 2.186 MeV, it is unstable to alpha emission, and will turn into 4He + d.