The very first time the car overheated it had a broken radiator (cracked on top); both the radiator and the thermostat were replaced. I drove the car for like a week without any issues, but now it overheated again. This time the coolant was boiling and was being pushed out the overflow in the reservoir. Any ideas what's going on? (is a 2005 anniversary edition)

 

Start with this. Report what you find. Someone should sticky these instructions, I've posted them in about a half dozen threads on my350/G35 driver and it always helps

Success story: https://g35driver.com/forums/engine-...erheating.html

Car cold
top off overflow tank
Jack up front end so radiator fill is highest point and radiator is at an angle to promote bubbles rising out of the fill neck
Buy funnel with taper on it. Cut funnel so you can tap it into the radiator fill cap and it will stay there/not leak as you fill it up higher than the radiator. (Or buy a lisle spill free funnel if you have time for amazon shipping). This is the secret
Fill radiator and funnel almost to top (distilled water or nissan coolant mix)
Squeeze lower and upper radiator hoses repeatedly to agitate the air bubbles out. Start with lower then upper and repeat. Fill funnel as necessary.
Start car with heater on 90 degrees but fan speed down low
Continue squeezing radiator hoses as it warms up for first 1 minute. You will see more air come out now that engine is running. Remember start at lower radiator hose.
rev engine quick a few times to about 3000rpm to agitate fluid in engine block
revisit and squeeze radiator hoses some more
Run car until radiator fans kick on. Don't run it much past this with the radiator open or it will suck a lot of coolant from your overflow when it cools down since the fluid is expanding at this point. I'd say 3-5 mins if it's warm outside.
Squeeze around some more and fill funnel as necessary
turn car off
remove funnel
top off radiator once more, don't squeeze around this time or you could suck air in
install radiator cap
verify overflow still full
drop car
start car
idle until radiator fans kick on
rev engine once more a bit
Verify that pressure is building in coolant system by squeezing upper radiator hose. You should not be able to flatten it completely Let us know what you find when doing this, it tells us a lot.
crack bleeder on passenger side, might get one last bit of air (assuming pressure is building)