I have to agree with @missileman. These are the most reliable “Chevrolets” ever built, but the owners’ care largely determines how long the car will last.
The most miles Toyota I ever rode in had 1.4 million kilometers (875,000 miles), but it was a well maintained taxi overseas with no salt on the roads…
Even with rough care, the car should be good for 250,000 miles or so, but the transmission will be the weak point without regular fluid and filter changes.
To answer @TommyPickles question, 500,000 miles is possible with very careful maintenance and good driving habits, but only in a dry climate with little salt used on the roads. If you don’t have the money or the inclination for good regular maintenance, 250,000 miles will likely be your limit.