Napalm-like...so, just an incendiary, or a gelling incendiary that sticks to flesh? For the former, I'm pretty sure thermite is an "anarchist's cookbook" level of incendiary that could be utilized (and would give all of those extra aluminum cans another use), but given the rapidity of the reaction, I'm not sure about area denial, which seems to be what you're after. For your delivery mechanism/manhack, at least, you could construct a flame fougasse as well - a large (55 gallon or so) fuel container containing mixed gasoline/petrol and oil with an igniting/projecting explosives to fire a blast of burning liquid over dozens of yards. Looking it up for more detail, it looks like a formulation of tar, lime and petrol gel was utilized later as well.
Finally, if you really want napalm, apparently it's also in some anarchist cookbooks, though I've obviously never tried it for myself. You can manage it with gasoline mixed with styrofoam (the latter dissolves in the former, apparently, until you end up with a sticky syrup that won't dissolve any more). That requires there to be styrofoam in the game, though. The other option in this cookbook is a 1:1 mix of gasoline and soap (flakes or shredded bar, but not detergents), heated in a double-boiler (water underneath) so the soap melts in the upper container, at which point you remove it from the flame and add gasoline, stirring until the agglutination thickens. In the game, that'd probably be two instruments with a boiling capacity, maybe some tool to powder the soap - a grater or the like), water (not consumed), fire or some heating source (not consumed), gasoline, and plenty of soap bars (apparently 10% by weight). I'm also seeing some people recommend powdered aluminum (replacing benzine, which is not a household product) or gelatin powder as a thickener to reduce separation issues. While it's not napalm, you can also gel gasoline directly with egg whites (85:14, with an additive such as salt, cocoa, sugar, aspirin, or coffee).
Keep in mind, though, that while I call these "anarchist cookbook" recipes, that kind of category also includes stuff like extracting pure RDX from C-4 and producing nitroglycerin from base materials, so don't take that as being easy or safe.
And I'm pretty sure I'm now on all sorts of fun watch lists. Again.
EDIT: Added some more details.
EDIT 2: Good heavens, that last paragraph was a train-wreck. Fixed. Also, turns out there is a napalm recipe already in the game. I did not know that. Also also, it was the modern gunpowder recipes that were removed rather than the primers, so I fixed that as well.