Values = new Dictionary<string, object>
{
    ...

    { "affinity", new Dictionary<string, object>() 
        {
            { "nodeAffinity", new Dictionary<string,  object>()
                {
                    { "requiredDuringSchedulingIgnoredDuringExecution", new Dictionary<string, object>()
                        {
                            { "nodeSelectorTerms", new object[]
                                {
                                    new Dictionary<string, object>()
                                    {
                                        { "matchExpressions", new object[] 
                                            {
                                                new Dictionary<string, object>()
                                                {
                                                    { "key", "<http://eks.amazonaws.com/capacityType|eks.amazonaws.com/capacityType>" },
                                                    { "operator", "NotIn" },
                                                    { "values", new object[] 
                                                        {
                                                            "SPOT"
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                } 
            }
        }
    }
}

using YamlDotNet.Serialization;

public static class StringExtensions
{
    public static IDictionary<string, object> DeserializeYaml(this string yaml) => new DeserializerBuilder().Build().Deserialize<IDictionary<string, object>>(yaml);
}