CREATE TYPE [dbo].[MyTableType] AS TABLE
(
    Id INT NULL INDEX ix UNIQUE WHERE Id IS NOT NULL /*Unique ignoring nulls*/
    , Sort INT NOT NULL
    , [Name] NVARCHAR(MAX) NULL
)

CREATE TYPE [dbo].[MyTableType] AS TABLE
(
    Id INT NULL UNIQUE
    , Sort INT NOT NULL
    , [Name] NVARCHAR(MAX) NULL
)

CREATE UNIQUE NONCLUSTERED INDEX idx_yourcolumn_notnull
ON YourTable(yourcolumn)
WHERE yourcolumn IS NOT NULL;

CREATE TYPE [dbo].[MyTableType] AS TABLE (
    MyTableTypeId int identity(1, 1),
    Id INT NULL,
    Sort INT NOT NULL,
    [Name] NVARCHAR(MAX) NULL,
    _ix as (coalesce(id, - MyTableTypeId)),
    unique (_ix)
);