Hazrat Qatadah was asked that if a person covers only his nose during prayer, what is the ruling on this? He replied that Hazrat Ikrimah has narrated that Hazrat Ibn Abbas (may Allah be pleased with them) considered it disliked. Hazrat Qatadah says that Hazrat Saeed bin Musayyib, Hazrat Nakha'i, and Hazrat Ata also considered it disliked. Hasan did not see any harm in it. Hazrat Qatadah says that I do not see any harm in covering the mouth.