Hi, Manish,
The LPC4367 has internal power-On Reset and watch dog, so in general, it is okay to use an RC circuit for the Reset pin, external watch dog is not required.
If you do want to use external Reset circuit, I do not think there is special requirement for the Reset circuit, anyway, you can consider UM805/UM811/UM812.
Regarding the external watch dog, I have not idea. But you can search it on Google.
BR
XiangJun rong