Option 1.
Change: $IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 8080 -j ACCEPT
To: $IPTABLES -A FORWARD -p TCP -s 0/0 --dport 8080 -j ACCEPT
Option 2.
What you are really looking for is to direct traffic from the FORWARD chain to the tcp_packets chain:
$IPTABLES -A FORWARD -p tcp -j tcp_packets