[{_id:1,v_name:"Hair Patch in Delhi",v_url:"https://www.testurlvideo.com",v_comments:[{"user":"Kush Khurana","comment":"Awesome Video"},{"user":"Nikhil","comment":"Keep up the good videos"},{"user":"Kush Khurana","comment":"Very good and Awesome Video"},]}]

db.collection.aggregate([{"$match":{"_id":1}},{"$project":{"v_comments":{"$filter":{"input":"$v_comments","as":"arr","cond":{"$eq":["$$arr.user","Nikhil"]}}}}}])