OP is talking about trans not engine.
FYI, some few trans designs DO have trans filters that only can be gotten to with a complete case breakdown.
The mech wanted to not remove the pan, that can be because many pans glue on now (no gasket on them at all) and then re-gluing makes them leak like hell to get complaints with every one you do. Can't blame him for that. The original glue job happened with trans upside down and easy to get to and most importantly BONE DRY at the sealing surface. One should try to re-glue up a pan with trans oil dripping all over the place, then you'll know what I'm talking about. Guaranteed leaks everywhere and then customer comes unglued next. Hah, hah.
The filters don't need changing in the vast majority of the cars anyway, and never did. Customers were trained very carefully to think they needed it though (corporate brainwashing) and we are the lemmings there. ATX filters really catch very little for most of their lives, at least until the trans begins to come apart, then they get used bigtime. Until then they will only have a few specks of matter in them. They NEVER clog unless the trans is already coming apart, and you will know it already by then. Or you better have.
On a Versa with drain plug, first be glad you got one. Second, USE it to flush and leave the filter alone.
The difference in trans type makes a big difference in price due to the fluid type used. $300 good for CVT, waaaayy too high if a standard type ATX there.
60K is really too long to run the fluid and I don't care what Nissan says, any company with transmissions going bad right and left right after the first fluid change like these do..........well, I am not going to listen there. I'd be looking at 30 or 40 to change it instead. For sure if a standard ATX, the fluid is burning by then. I changed my standard ATX fluid last year (36K miles or so) with Ford fluid and works fine, saved money doing it too. Nissan fluid is too expensive. You really got no other choice though on CVT and locked into Nissan fluid there.