Why is my car overheating?

We're dealing with an ignorant owner who hasn't provided enough information. Could be a water pump problem. Could be a clogged radiator. Could be a failing head gasket. Could be failed radiator fans or the electronics that control them. Could be a failed thermostat. 

Bad COLLING FAN SWITCH< the WRONG COOLANT! It MSUT be ONLY GENUIONE NISSAN coolant! TRASH trapped between the RADIATOR and the AC CONDENSER! Where LEAVES< DEAD GRASS, TWIGS, BUGS and ANIMAL DROPPINGS and NEST materials have collect for YEARS! REMOVE the upper RADIATOR SUPPORT and clean this space with GUNK ORANGE original engine cleaner at a DIY car wash! This improves AIR FLOW through the RADIATOR and the AC condenser! If this does NOT do it, tak to a NISSAN DEALERSHIP and get a COOLANT SERVICE DONE! Like I said ABOVE< you should NOT use PRESTONE< PEAK or ANY other coolant but the FACTORY COOLANT! You may have bought this USED and the PRIOR owners did use the wrong coolant in there! EB SURE to turn your AC ON to see if the FANS SPINS! You may ALSO have a failing COOLNG FAN RELAY! CHECK all your FUSES and clean the ENGINE BAY with GUNK ORANGE original to improve CONECTIONS! ALSO>>> never use REGAULWAX BASED OIL! In TIME< it will make unwanted SLDUGY TARRY coatings on the entire ENGINE INSIDES< and this will HOLD IN EXTRA HEAT! get a  MILD sludge removal treatment! I use AMSOLPOER FOAM mixed with GUNK on the INSIDE of the engine to remover any unwanted COATINGS! I drive it for HALF HOUR before oil change GENTLY with HALF can of EACH! AMSOIL POWER FOAM is UNREAL It destroys SLUDGE and TARS a and VARNISH on contact! >>CLEANING THE ENGINE BAY is VERY IMPORTANT so the ALUMIINUM engine parts can BREATHE! And REG oil should NEVER be used! PENNZOIL ULTRA PLATINUM Is good for MOST cars, and is made from NATURAL GAS! It wil REMOVE ANY coatings FORMED ONTEH inside OF THE engine THAT IS baking INTO PARTS! it will  clean the timing chain AND a chain tensioner, as well as the the valve lifters! modern MULTI VALVE engines WITH variable cam timing simply cannot be using regular wax based oil or ASH BASED Valvoline< an oil that NO FACTORY on earth will USE! Amsoil FOR Asian cars, is good for 25,000 MILE oil change intervals WITH on OIL filter CHANGE MIDWAY! i am an and i know  what works AND what does not WORK! Keeping the engine bay clean is a must for any car AND AT 100,000 MILES, You should go to the dealer and get all the fluids changed using ONLY only genuine Nissan fluids from the parts department, INCLUDING the brake fluid! Once it is very dark brown IT IS A dead fluid and becomes acidic liquid sandpaper! The benefits of Pennzoil ultra oil ARE plenty! longer LASTING o2 SENSORS, converter and exhaust! better MILEAGE AND power, longer ENGEIN LIFE! cleans AS YOU drive! It is AWESOME and removes all unwanted  internal coatings from YEARS of BAD oil use. IN A FEW weeks! When it gets VERY dark< change it Again The second time, it will last even 

Sounds like the fan is not kicking in and you are just relying on the car motion to move the air.   Should be fairly cheap and simple.

Check to see if the thermostat is stuck.  Is the fan working properly?

Check if the fan is engaging.  Check for a bad water pump.