Full list of all 36 NASCAR '15 achievements worth 1,000 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
You took part in 100 online races
You took part in 50 online races
You won the Sprint Cup in Single Season Mode
You qualified on Pole 20 times
You have driven as 10 different drivers
You researched everything in the R&D department
You won the All-Star Race
You finished the first season of your Career
You won the Sprint Cup while playing your Career on at least 90% difficulty
You won the Sprint Cup while playing your Career
You invested in all areas of the Race Shop
You signed 10 sponsors to your car
You made it to pit road with a flat tire
You DNF'd from a race because you critically damaged your car
You were involved in a wreck at Talladega
You won a Career race using only refurbished parts for your car
You were the Lucky Dog driver during a race
You passed a total of 250 cars
You won the Sprint Cup in Chase Mode
You ran a custom tuning setup in a race
You ran 10 laps in a single Track Testing session
You won 20 online races
You won a season whilst playing with a League
You won 10 online races
You won a race with the HUD turned off
You saved the replay of an online race
You won a race while driving a Ford
You won a race while driving a Toyota
You won a race after Qualifying first and leading the most laps
You took a picture using Photo Mode
You created a custom scheme in the Paint Booth
You made a custom brush in the Paint Booth
You won your first online race
You won a race while driving a Chevy
You started and finished a race without any driving assists
You took part in your first online race