Your syntax will be as follows, because you need both sender and receiver you need to join to users table twice.
CREATE VIEW SomeFancyName
AS
SELECT s.profile_pic AS sender_pic
,r.profile_pic AS receiver_pic
FROM Chats c
JOIN users s
ON c.sender_id = s.user_id
JOIN users r
ON c.receiver_id = s.user_id
now you can add columns that you need from each