Handling nested struct in Go Validator.v2

I have been using Go Validator.v2 for field validations and it works elegantly for my non-struct typed fields. However, when it comes to handling struct-based fields (within the original struct), there is no documentation about it whatsoever. https://pkg.go.dev/mod/gopkg.in/validator.v2

I know the v10 has support for it, but I prefer the built-in regex support in v2. Is there anyway I can customise validation for these struct-based fields? e.g.

type user struct {
   Name            string   `validate:"nonzero"`
   Age             int      `validate:"min=21"`
   BillingAddress  *Address  ???

}

I wish to validate the BillingAddress field as shown above, or do I simply write the validation tags in the Address model and it will automatically validate it, too?

Thanks and any pointers are appreciated!