Not too long ago, I substituted chestnuts for jackfruit seeds. Now, jackfruit seeds (AThalya - Marathi/ Bikand - Konkani/ Champa ni GoTli - Gujarati) are readily available at our local Indian grocers. They come peeled, sliced and frozen. It's very easy to make any curry. My MIL suggested adding them to the bittergourd stir fry.
Kaarela ane Champa ni Gotli nu Shaak
Bitter Gourd with Jackfruit seeds
1 cup jackfruit seeds
2. Add bitter gourd pieces and sauté till they are semi cooked.