Empty jackfruit into a strainer and rinse. Transfer jackfruit to the bowl of a food processor and pulse a few times until chopped. Don't over-process; the jackfruit should have texture to it. Alternatively, you can chop jackfruit with a knife.
In a large bowl, mix garlic, syrup, mustard, chili powder, cumin, salt, and cayenne pepper. Transfer jackfruit to the bowl and stir everything together.
Place a medium pan over medium heat and drizzle with a little olive oil. When the oil is warm, add the jackfruit. Cook for about 10 minutes, stirring occasionally. When jackfruit is cooked through and spices are fragrant, add black beans and BBQ sauce and stir to mix. Cook for another 8 to 10 minutes. Can be made several days in advance and reheated before making nachos.
To make the coleslaw, whisk together mayonnaise, vinegar, syrup, lemon juice, salt, and pepper. Add sliced cabbage to the bowl and toss to coat the cabbage with the dressing. Set aside. When ready to serve, drain off some of the excess liquid and toss again.
To make the sour cream, drain and rinse the cashews and place in a blender. Add water, lemon juice, and salt. Blend on high speed until smooth and glossy, stopping to scrape down the sides as necessary. Add more water, by the tablespoon, if necessary. Taste and adjust the flavor by adding more lemon juice or salt. This can be made several days in advance and chilled or make and serve immediately. The sour cream will thicken up after chilling. Thin with water if necessary after chilling.
To make the tomato-avocado salsa, place all ingredients in a bowl and toss to combine.
To assemble nachos, arrange a layer of corn chips on a large platter or smaller plates. Spoon about half of the jackfruit-bean mixture on top of the chips. Spoon on the coleslaw, then the tomato-avocado salsa. Drizzle with cashew sour cream. Repeat layers using remaining ingredients. Serve immediately. If adding vegan cheese, place under the broiler for a few minutes to melt.
