Nothing in his recent comics has shown that he has, tho. I have everything from Annihilation to Current (WoK) and there hasn't been any indication of an upgrade to Nova's previous power levels, if anything, he's weaker as he now shares the Nova force with a ton of other ppl as well as the Shi'Ar Nova Prime (who was never shown on panel to have lost the Nova Prime abilities, tho I think he should have already).
True, but because he flatly stated that Firelord was well beyond him in power when he was arguably at his strongest (Annihilation w/full Nova Force), means that he probably can't.
Nova didn't lose to Surfer, he was outright totally outclassed, while Firelord has been shown on panel to hold his own against the Surfer. However, this is arguable because Surfer could have been upgraded (still has to be proven on-panel) after Annihilation and would thus probably outclass Firelord as well IF such an upgrade existed.