Hi,

Yes .We can add a child manufacturing order inside a main manufacturing order.

While creating Bill of material we have an option to add components which are used for the manufacturing .

If the component is not having enough quantity, Or if it should be manufactured before the parent manufacturing order , we have an option to set route for the component product under the inventory tab for the product.Enable Replenish on Order(MTO) and Manufacture 

Then if you are creating a manufacturing order and the component is not available then it will create a child manufacturing order in it .

If the child manufacturing order is completed then only the parent manufacturing order will be started.

Regards