uci add chilli user
uci set chilli.@user[-1].username='user1'
#dont forget to add a pinch of salt (the password will be 'pass1' in this case)
openssl passwd -1 -salt abcd pass1
$1$abcd$PDaCHs3hGO3GYSrsEZtAl/
uci set chilli.@user[-1].password='$1$abcd$PDaCHs3hGO3GYSrsEZtAl/'
uci set chilli.@user[-1].group='default'
uci commit
/etc/init.d/chilli restart