timing chain cover removal

i am replacing the head gasket on a 2008 nissan frontier 2.5l 4cyl. i can’t seem to get the timing chain cover off even tho it looks like all the screws are out.
I’ve seen people saying i have to take the oil pan out and i did but i can’t see anything underneath still connecting the timing chain cover.
If anybody knows what i’m over looking pls let me know. Thanks