Perfect, the pictures help allot, and I have repaired cowlings and wheel pants that were equally damaged in this way. That looks like gel coat with an epoxy layup to me. Bad idea if it is...
1. Wash with really soapy dish soap, rinse and dry thoroughly.
2. Chip away everything that comes off easily.
3. Thin CA everything else, all edges and micro cracks on the exterior side.
4. Abrade interior with 80 sand paper, clean and place 2 plies of 4-6 oz. plain weave cloth and your favorite epoxy resin on the interior area that is effected and allow to cure.
5. Abrade exterior with 80 grit sandpaper, preferably using a DA sander with 80 grit sanding pads
6. Sweep lightly with bondo, sand, and repeat as needed.
7. place one ply of 3/4 oz. on the exterior and your favorite epoxy resin.
8. After full cure, feather edge glass while sanding entire cowling, clean, prime and sand as needed, and topcoat.
Bob