In a large bowl, combine the brown rice cereal, almonds, pistachios and chia seeds. In a small saucepan over medium heat, melt the honey and peanut butter until they are a warm, pourable consistency, about 3 minutes. Stir to combine and fold into the dry ingredients.
Transfer the cereal-nut mixture to an 8-inch square pan lined with parchment paper. Press it into a compact even layer. Chill in the refrigerator for 1 hour until set. Slice into 16 equal squares.
Place the chocolate and coconut oil in a microwave-safe bowl. In 30-second blasts, melt the chocolate. Stir to combine and drizzle over the bars. Sprinkle with flaky sea salt. Return the bars to the refrigerator to let the chocolate harden, about 30 minutes.
Leftover bars should be stored in an airtight container in the refrigerator.