There's a 2x4 that most of the rest of the tile board is nailed to.Was the tileboard up there when you took possession of the house? Is there a way to look behind it? Might be worth taking it down and fixing the situation back there.
The part that won't attach is just above the blinds towards the right side. You can see 6 little nail holes where I attempted to nail it in.I like the post because it assumes that any of us know, of the five products in the 1st photo, or the two in the 2nd photo, which you are talking about, based upon "It's not attaching in this one spot. Nails go right through it, and I can't clamp it from that angle to use any type of adhesive.", which does not describe what, why, when, or where.
There are limits to are intuition.
I find the OP"s terminology, interesting, because "tile board" to me, is the product placed on shower walls.
He said that he nailed some nails, but not what size nails. He also said there is a 2x4, so the nails were too short or missed, because the 2x was not on the flat.
He could use longer nails on an angle, or take the blinds down and insert some adhesive and prop the panel up until it dried.