No, NCERT alone is not completely sufficient, but it is helpful. NCERT can clear your concepts, but it is not adequate for the practice purpose as NCERT have only basic concept in it. Some questions are asked in NEET physics which are not even mentioned in NCERT. The competition in NEET is rising so you need to pull your socks to get more score. If NCERT mentions any concept without explaining it in detail then it is your duty to cover up the complete concept of that topic.

You may also go for some online courses to get additional and guidance support.