What reasons above. All are sort of faulty to varying extents. Didn't even take into account that this is SFDM Natsu.
Look, guys. Natsu already vaporized a lake as well. Unless someone mentions something better for Escanor, Natsu won't be bothered by Escanor's fire and heat. In fact, it's supposed to be the other way around. There's nothing that says Escanor's heat is better than Natsu's according to what I've seen so far. It's been some time since I read NNT. Just cuz his ability is hyped in his own verse doesn't mean so much in a crossover fight. And if you want to mention feats that are not quantifiable, I'm going to mention Natsu burning light, death magic, existence erasure, and setting either his soul or Zeref's on fire.
"Sunshine"
First off, I don't even know why this is important. Fire and heat? Natsu resists that and can eat fire. The light it radiates? Natsu resists, and can eat light with Sting's power, and has also burned it before. If you mean he can use it to blind Natsu, the dude has enhanced senses. Not going to work.
"Rhitta"
Normally yes, I'd see the usefulness of this since it gives Escanor an advantage in melee due to its extended size and its sharpness, meaning it'd be more dangerous compared to Natsu's shorter range and blunt force damage with his fists. But SFDM Natsu? He can just use Gajeel's power and enhance his offense and defense by turning his body into iron and steel, or eat Rhitta for good measure. What's Rhitta made of? Iron? Steel? Partly wood? Dragon Slayers have eaten all and worse.
"Statistics Amplification"
I mean...seriously? Well yes, it's true that Escanor's power increases due to the nature of his ability. But adding to Natsu being able to eat Escanor's fire, light and whatever Rhitta is made of, he can eat the air around them to boost himself, can boost himself with lightning, and has rage power on top of his power increasing depending on his emotions.
"AP"
How does Escanor have an advantage here? He's scaling to AM Meliodas who's baseline or slightly above it because I see no calc and it looks to be based on him being >>>> his demon form? Natsu with Igneel's power almost killed Base Zeref who's >>> 121 gigatons Irene. SFDM Natsu >>>>>> DF + FDKM Natsu >> Natsu with Igneel's power >>> FDKM Natsu, I think. In any case, I don't think Escanor has a power advantage, but I'll look more closely later.
Sooo, Natsu is either resistant to, and can eat Escanor's stuff, can bypass Escanor using Rhitta to gain an advantage in close quarters, and has ways to counter Escanor's power rising. And this is not even factoring Natsu having the ability to paralyse with lightning, immobilize with Sting's stigma, Rogue's ability to become intangible, Poison Manipulation, and other versatile options.
I...vote for Natsu.