Preheat your air fryer to 400°F.
Slice the russet potato into 1/2-inch thick wedges, toss with half the avocado oil and a pinch of sea salt.
Place the potato wedges in the air fryer basket and cook for 15-20 minutes, shaking halfway through, until golden and tender.
While the chips cook, whisk together the flour, baking powder, sea salt, black pepper, and light beer in a small bowl until a smooth, thick batter forms.
Pat the cod fillet completely dry with paper towels, then dip it into the batter to coat all sides thoroughly.
Lightly brush or spray the remaining avocado oil onto the battered fish and place it in the air fryer basket next to the chips (or in a separate batch).
Cook the fish at 375°F for 10-12 minutes until the coating is crisp and the cod is opaque and flakes easily.
Serve the fish and chips hot, garnished with fresh parsley and a fresh lemon wedge.