NZEC error is a runtime error and occurs mostly when negative array index is accesed or the program which we have written is utilizing more memory space than the allocated memory for our program to run. While coding in various competitive sites, many people must have have encountered NZEC error. There are a lot of posts with NZEC error. Why m i getting NZEC (Non Zero Exit Code) for my program? 2 Likes. NZEC stands for Non Zero Exit Code. I suppose the codechef question is this one.