Adding physics bodies to all tiles on an SKTileMapNode - swift

Question

I'm trying to make a simple game in the latest version of Xcode. I use a TileMap that is pretty simple. I'm trying to figure out how to add a physics body to each and every tile. I'm stuck at getting the position of each tile and adding an SKNode there. Any way at getting the position of each tile would be extremely helpful. All the code below is in didMove(to: view)
let tileSize = grassTileMap.tileSize
let halfWidth = CGFloat(grassTileMap.numberOfColumns) / 2.0 * tileSize.width
let halfHeight = CGFloat(grassTileMap.numberOfRows) / 2.0 * tileSize.height
for node in self.children {
if node.name == "grassTileMap" {
grassTileMap = node as! SKTileMapNode
}
for col in 0..<grassTileMap.numberOfColumns {
for row in 0..<grassTileMap.numberOfRows {
let tileDef = grassTileMap.tileDefinition(atColumn: col, row: row)
if tileDef == nil {
print("no tile here")
} else {
let hitboxTileNode = SKSpriteNode(color: UIColor.clear, size: CGSize(width: 35.5, height: 35.5))
// I need to set the position of each tile to hitBoxTileNode here
hitboxTileNode.anchorPoint = CGPoint(x: 0, y: 0)
hitboxTileNode.physicsBody = SKPhysicsBody(edgeLoopFrom: hitboxTileNode.frame)
hitboxTileNode.physicsBody?.affectedByGravity = false
hitboxTileNode.physicsBody?.isDynamic = false
hitboxTileNode.physicsBody?.pinned = false
hitboxTileNode.physicsBody?.restitution = 0
hitboxTileNode.physicsBody?.friction = 0
addChild(hitboxTileNode)
}
}
}
}