Probably one of the most consistent Incineroar decks out there. Feel free to make changes, it's not perfect. If you can see, it's pretty much a Charizard ex deck, but with Incineroar. But, Incineroar can get early OKHO's with relicanth after taking damage. Energy acceleration usually isn't a problem because of Hustle Play (Incineroar's Ability), and the use of magma basin, but the better the opponent, the less they will bench, so it can be a problem if you don't find energy early. That's why I put earthen vessel in, this card can be taken out if you feel like your energy acceleration is fine. I've also tried using Mela in this spot, Mela can come in clutch every once in a while but isn't usually as useful.
Play this deck like Charizard ex, get your Pidgey, Rotom V, and Litten down then use Instant Charge (Rotom V's ability). I prefer going second because it allows me to use preferably Arven, otherwise Iono first turn. Use Arven to get your pokemon in play and find forest seal stone with it. Use that next turn to get your Pidgeot ex and Incineroar ex in play. The biggest problem with this deck is getting the Pidgeot ex and Incineroar ex in play on the second turn. If you have the right cards in hand it usually get's set up no sweat, but like half the time you can only get your Incineroar ex set up second turn, especially if you go first. Use Radiant Charizard late game as your one-prize attacker. You can make the argument to put in Radiant Greninja if you want to have more consistency, but that late game attacker is usually better. Overall, this deck is mostly solid, and is fun to play!!