No, attending a coaching institute is not mandatory to succeed in JEE Main. Many students qualify for the exam through self-study by thoroughly studying NCERT textbooks, practicing previous years' question papers, and using online learning resources. Coaching institutes can provide structured guidance, study material, and regular mock tests, which may help some students manage their preparation better. However, disciplined self-study combined with consistent practice and conceptual clarity can also be sufficient for achieving a good score in JEE Main.