Create an object from nested struct definition in GoLang?

Is there a way to create an object from a nested struct type

func main() {
	car := Car{}
	var wheel Car.Wheel
}

type Car struct {
	Wheel struct {
		name string
	}
}

I have a deep nested json. I am interested in operating on many of these nested structs separately.
I want to access the struct definition through the “root” definition . Something like Car.Wheel instead of explicitly defining type Wheel struct for many of my nested objects in the json

> Is there a way to create an object from a nested struct type

No, because there's no such thing as a "nested struct type". You don't have a type Car.Wheel, you have a type Car, with a field Wheel; that field's type is the unnamed type struct { name string }. You cannot refer to an unnamed type; it is unnamed. To refer to a type, you have to name it. You could do:

var wheel struct { name string }

And you'd be able to assign between wheel and Car.Wheel, because they're the same type; however, this is not particularly convenient (you'd have to write out the full type definition everywhere you use it), and it means you can't define any methods on the type, which may or may not be a limitation you care about.

Generally speaking, in Go, you just want to define a named type for each type you want to use, and those definitions would each be at the top level:

type Car struct {
    Wheel Wheel
}

type Wheel struct {
    name string
}

Are you looking for something like this:

package main

import "fmt"

type Car struct {
	model string
	wheel Wheel
}

type Wheel struct {
	name string
}

func main() {
	car := Car{model: "Toyota"}
	car.wheel.name = "my wheel"

	fmt.Println("car model: ", car.model)
	fmt.Println("car wheel name:", car.wheel.name)
}