A Toyota will outlast either of those, but between those two I'd pick the Subaru. (Nissan quality has been in the toilet for ages and their CVTs have a terrible reputation.)

You should be able to get a lot more than 143K miles out of a new Legacy if you change the CVT fluid regularly instead of listening to Subaru of America's "sealed transmission/lifetime fluid" nonsense.

an Altima vs Subaru Legacy

But why those two? They're both very "meh" cars.

I am considering buying a new 2023 Nissan Altima with the Naturally Asperated 4 cylinder engine

It's pretty weak from a mechanical standpoint, especially the CVT.

Also, when I recently was shopping for my car, what shocked me was how poorly equipped Nissans were - "Premium" models were equipped worse than the 8 year old base model $17k (msrp) Ford I had at the time...

Looking on Nissans website the Altima is no different: NO ProPILOT, NO AEB, NO LDW, NO Trace Control, NO Brake hold, NO Dual Zone Temperature, NO rear passenger vents, NO leather on the steering wheel, A TINY infotainment screen, NO CarPlay (!?), NO AndroidAuto (!?) - FOR $25,290??.

Probably the least amenities in any new car over $15k, and no redeeming qualities I could find.

I would also consider a 2023 subaru legacy with the naturally asperiated 4 cylinder

A MUCH better car.

Unlike the Nissan, this car has some basic amenities you'd want on the model that's one step above the base.

(Although this still requires checking.)

And mechanically these are reasonably well built - it was the base for the outback.

Keep the engine oil and CVT fluid clean and it will probably last you for a long time (125k-150k+ miles)

Out of the two cars listed, which car would you say would last long?

Definitely the Subaru.

I still definitely recommend looking the Camry - they have a conventional automatic transmission, far better engines, way more reliable, nicer to drive and better equipped.