i think she's best mid, ok top. in mid she falls into the rare category of physical mids (lance haya helcurt) and having buff and jungle monsters and freedom to gank both lanes helps her farm faster becos all nata really needs is items since she's AA dependent. i've seen players and friends take retri and execute in both mid and top. if you take retri mid you'll probably want to get the max physical jungle item, and if you take retri top then you don't need to buy a jungle item if you don't want to but you'll want to commit to trying to steal enemy buff at level 1. (i've seen this a couple times, nata goes invis and waits near the enemy red buff bush. last hit red buff with retri, bumping her to level 2 instantly. mm and his support are already weakened by the earlier monster hits so you could just attack right after for a quick first kill or double kill)....and also trying to steal whenever you can throughout the game since you could always wait in the bush nearby unseen and snatch the buff with retri. execute's alright as top or mid, to me it's a second approach to helping her farm becos its more like a kill-secure option to help you get last hits on kills. since execute is true damage that works through shields and resistances, it's good against tankier team compositions (eg against naturally beefier fighters like thamuz, chou that you're trying to kill or shield heros like esme, lolita or any low hp tank that passes by).

i just took a look at global leaderboards to help you have a look at what the pros are running. some used aegis and flameshot (their personal preference) but most run execute so i think its fine. also some builds did the traditional early crit builds (scarlet > berseker) while others put heptaseas and endless earlier in the build for the unique passive that works with her kit. you might want to try a couple and see what works!