It is propaganda that Musharraf forgave crimes of any criminals (except obviously Nawaz and Shahbaz). Actually, Musharraf did not pardon or forgave any criminals or their crimes except crimes of Nawaz and Shahbaz whom Musharraf gave pardon in 2000. As for NRO, that is not pardoning or forgiving crimes of criminals. It is to do with withdrawing cases of accused, the cases that were lingering on for over 10 years without convictions (and that mean, NRO does not apply to anyone who was accused after military takeover in 1999 and cases started).
As for continuing in power as President, that was not dependent on NRO, as Musharraf did not waited to get elected after 2008 election on votes of those who benefitted from NRO (so no one in their right mind except propagandist could say that Musharraf’s victory in presidential election was due to NRO).