You don't even need yeast if you have soda and can make a biscuit flour, or use the flour ground from biscuitroot as it is a self rising flour for the crust.
Or you can go hard core and make hardtack for your crust, (Some of the thin crust pizzas I have had I think used hardtack anyway
)
You could also use a flour made from cattails, if you add the pollen it has a really moist nice flavor.
Once you have the crust, you can use whatever toppings you have, I made one of the best pizzas I ever had using deer hamburger, bear back-bacon and antelope sausage.
Wild onion or camas or even cattail can be the vegetables, for a sauce if you don't have tomato you can use another fruit such as chokecherry (watch out for the pits) or wild plum.
If you don't have oregeno and basil, there are other natural plants you can use such as sage, or perhaps wild mint.
Probably won't have any cheese, but if you are worried about it being too dry, you can always add a few pieces of animal fat that will keep the concotion moist, and will cook down to crackin's which will add to the pizza too.
If you don't have a dutch oven, simple enough to make a stone oven with a few flat rocks and some mud.
May not taste like Chicago's finest, but it would be a break from MRE's, which I don't have anyway
If I were to do something like that in the wild, I would probably form a pasty or pocket with it so it is easier to eat without utensils.
One thing to remember in a survival situation, most wild edibles are edible because they won't kill you, not because they have a great flavor.
Many wild foods are actually pretty nasty, but they have the necessary carbs or proteins you need to keep going.
The biggest thing you miss when on a wild edible diet alone is salt and sugar. Salt can be obtained from natural sources, but sugar is tough to find. Knowing what grows in your area, being able to identify it, and know how to process it can go a long way to making it through whatever the situation is you are in.