Why not?
One can see Zeus as Upgrade for the "Thunder Balls" this way Prometheus can become Upgrade for the "Heat Balls". Then only an Ice Monster as an upgrade for the "Cold Balls" missing.
Alright first we have to remember that Zeus and Prometheus are not random objects that someone can control, they are living things that can think and act for themselves. Next Prometheus is not gluttonous like Zeus is, and was shown to be far more loyal towards Big Mom than even Zeus.
The only reason why Nami was able to "control" Zeus was because Zeus was gluttonous for those thunder eggs, also during the WCI arc there were plenty of chances for Nami to take Prometheus as well but it never happened. You have to remember that both Zeus and Prometheus have different personalities, and that Prometheus is not gluttonous like Zeus is.
Also just my personal opinion but Big Mom losing another homie would be really bad, and Nami shouldn't even get another homie. It would make her clima-tact feel useless as she would be relying more on the homies, and it won't feel like her own powers because she would technically be using Big Mom's powers.
The only way I would have no problem for Nami to have homies, is if Big Mom gets redeemed and makes personal weather homies just for Nami. Also there is a slight chance that Nami might not even keep Zeus, and that later on during the arc Zeus will either go back to Big Mom or Big Mom will kill Zeus.
If Oda is going to have Nami take Prometheus, he would have to change some stuff and imo add some bs writing for that to happen.