Mix salt, allspice, hot curry, and cardamom in a small bowl. Set aside until needed.
Place 1 cup of chicken broth and 2 chicken breasts in an Instant pot/pressure cooker. Lock the lid and set the vent to "seal."
Select high pressure and set the time to 15 minutes. It will take approximately 5-7 minutes for the pressure to build up and for the counter to start counting down. When the time is up, do a quick release.
While the chicken is cooking, mix the meatball ingredients in a bowl and form into small meatballs approximately 1½ inches in diameter.
If you plan on adding sliced boiled eggs as a topping, and I recommend that you do, add 4 eggs to a medium pot and cover with cold water. Bring to a boil then turn off the stove and cover the pot with the lid. The eggs will be ready in 12 minutes.
Next, peel and cube the potatoes and slice the remaining onion.
Remove the chicken when done, and pour the broth out into a measuring cup. Top off with additional broth to make 2½ cups.
Once the chicken is cool enough to handle, shred and season with 1 tablespoon of biryani seasoning.
Wipe the pressure cooker clean and add 1 tablespoon of oil. Select "saute." Fry the meatballs until they are brown on all sides.
Remove the meatballs and add 1 tablespoon of oil to the pot. Season potatoes with 1 tablespoon of the biryani seasonings and brown on all sides for 2 to 3 minutes. Add sliced onions and cook for a few additional minutes.
Meanwhile, wash and drain the rice. Stir into the potatoes and onions. Mix the remaining biryani seasonings into the chicken broth. Pour over the rice and mix to distribute the spices evenly.
Add the chicken and meatballs on top of the rice. Lock the lid and set vent to "seal."
Select "pressure cook" and set the timer to 5 minutes. When the time is up, do a "natural release" for 10 minutes.
Meanwhile, add the last tablespoon of oil to a medium skillet and heat. Add slivered almonds and stir until they begin to brown. Add the raisins and continue stirring until toasted, but not burned.
When the rice is ready, "vent the seal." Mix the meatballs and chicken in with the rice until all the ingredients are incorporated.
Serve the biryani topped with the toasted almonds and raisins. Add sliced boiled eggs around the plate, if desired. Biryani is usually served with a side of Middle Eastern salad.