How to use ASP.Net Core Cookie Middleware and sign the user in within a Nancy module

AuthenticationModule.cs

public class AuthModule : NancyModule
{
    public AuthModule()
    {
        Post("/login", async _ =>
        {
            var myclaims = new List<Claim>(new Claim[] { new Claim("Id", "SOME USER ID FROM SOMEWHERE!!") });
            
            var claimsPrincipal = new ClaimsPrincipal(new ClaimsIdentity(myclaims, "MyCookieMW"));

            await this.Context.GetAuthenticationManager()
                    .SignInAsync("MyCookieMW", claimsPrincipal,
                        new AuthenticationProperties()
                        {
                            AllowRefresh = true,
                            ExpiresUtc = DateTimeOffset.UtcNow.AddMinutes(20),
                            IsPersistent = false
                        });
            
            return Response.AsRedirect("~/");
        }
    }
}

NancyContextExtensions.cs

using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Http.Authentication;
using Nancy;

namespace MyApp
{
    public static class NancyContextExtensions
    {
        public static AuthenticationManager GetAuthenticationManager(this NancyContext context, bool throwOnNull = false)
        {
            object requestEnvironment;
            context.Items.TryGetValue(Nancy.Owin.NancyMiddleware.RequestEnvironmentKey, out requestEnvironment);
            var environment = requestEnvironment as IDictionary<string, object>;
            if (environment == null && throwOnNull)
            {
                throw new InvalidOperationException("OWIN environment not found. Is this an owin application?");
            }
            return environment != null ? ((Microsoft.AspNetCore.Http.DefaultHttpContext)environment["Microsoft.AspNetCore.Http.DefaultHttpContext"]).Authentication : null;
        }
    }
}

Startup.cs

public class Startup
{
    public void Configure(IApplicationBuilder app)
    {
      app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AutomaticAuthenticate = true,
                CookieSecure = CookieSecurePolicy.SameAsRequest,
                AuthenticationScheme = "MyCookieMW",
                CookieHttpOnly = true,
                SlidingExpiration = true,
                CookieName = "MyCookie", 
            });

      app.UseOwin(x => x.UseNancy());
    }
}