2012 Sentra- loose plastic wheel covers and under engine cover

[briangomes]

So the plastics wheel covers are loose or they rattle around. The nuts are tight but there's still wiggle. How can I fix this?

Also the black plastic cover under the car is hanging down towards the middle, like its sagging. This also rattles. It looks like it is missing some screws or something. Any idea what parts I should buy?https://fetlife.vip/inro.in/mobdro/https://inro.in/tutuapp