Typescript Jest says mock or mockReturnedValue do not exist on types I wish to mock

Cast the mock method to jest.Mock, ie

import axios from "axios"
import Request from "./Request";

// Create an Axios mock
// Don't worry about the order, Jest will hoist this above the imports
// See https://jestjs.io/docs/manual-mocks#using-with-es-module-imports
jest.mock("axios", () => ({
  create: jest.fn()
}))

// Customise the `create` mock method
(axios.create as jest.Mock).mockReturnValue({
  get: getMock
})