I used to own a 1996 sentra, which uses the same engine which I had flushed the tranny, coolant and power steering fluids. It was the best used car I've owned with double miles than yours.
You are just fine using the cheap Valucraft "green antifreeze" jug from your local Autozone or equivalent from Discount Auto Parts.
No use buying Prestone universal coolant.
Good luck with the car. They are super reliable so as long as maintenance is kept up.
I had mine for over 2.5 years with 220k miles initially and up to 260k miles before trading it for my current car. It had the original engine and automatic transmission. AC compressor was replaced by previous owner.
Only thing I recommend you do is replace the valve cover (entire thing) since the rubber grommets around the spark plugs harden and allow for oil to get in the spark plug hole and some valve covers do not have these rubber grommets interchangeable, like mine did. Another tip, if and when you do replace the valve cover, look inside the timing chain compartment and look at the upper timing chain tensioner. If you see metal UNDER the chain, replace that tensioner ASAP because if you don't the metal shavings can wear out the chain and clog the oil pump and kill the engine. Replace the tensioner even if you see some wear in the hard rubber pad on it (people have good luck with Beck Arnley branded tensioner as it's made in Japan). Third tip: Replace the crankshaft pulley and seal as the seal within the pulley tends to wear out and leak oil - so does the seal behind the ignition coil (mine leaked from it, but very little), replace that too. Fourth tip: replace distributor cap and ignition rotor and wires (which I'm sure you know already to do).
Also, the odometer and speedometer tends to cut out in these cars and it's either a problem with the vehicle speed sensor or faulty electrical connection in the dashboard, behind the odo and speedo.
nissanforums.com was and should still be very helpful with further maintenance tips and how-tos.
