The Bleeding edge downscales from Thanos, who is 5.8 (Almost 6) Gigatons. While Akame upscaes from 1.2 Gigatons. So Iron Man has the AP advantage here as well as the LS (Class T vs At least Class M). Meaning in close combat he can physically overpower her.
Iron Man has much better range options as well and is an overall more versatile fighter. He could easily trap her with his nanotech, something Akame would likely have struggle getting out of due to lower AP and LS. He can just stay at a distance and shoot her down with his multitude of range weapons. He can block her attacks with his shields. Iron Man could also analyze her fighting pattern and counter her moves in hand to hand combat.
And Akame's trump card, the murasame, likely won't work that well against Stark because she needs to be hitting his flesh in order for he poison to work, and ya know, Iron Man has armor stronger than her AP, as his Armor was able to take several hits from Thanos before breaking.
In conclusion, Akame's main attacks wouldn't work against an armored opponent like Iron Man, and the fact Iron Man is stronger, has better versatility, and laughably better range would mean he should Low-diff this.
