All Green Lantern can really do is slow Thor down. I can't see him killing the Thunder God. If he can, what are his feats?
Thor's durability cancels out Green Lantern's attacks. Thor has tanked numerous explosions, strikes from equally or stronger creatures, and laughed off Iron Man's weaponry. And even if Green Lantern somehow manages to fatally wound him, Thor's hammer--Mjolnir--can rejuvenate him. Thor's strength is very impressive. It's comparable to the Hulk's, which is beastly in its own right. It took only a few tries to break free of a cage designed to hold the Hulk (he would've done it sooner had he not been bouncing off its walls while it was falling very rapidly from the sky). It wasn't hard for him to damage Iron Man's armor. Had he gone all-out, he would've ripped Tony apart with ease. Combined with his very powerful lightning attacks (e.g. reshaping the Frost Giant landscape and eviscerating the Chitauri leviathan creatures) and other weather manipulating abilities, Thor wins.