create table #SuspectColumns (
    TABLE_SCHEMA sysname,
    TABLE_NAME sysname,
    COLUMN_NAME sysname
)

declare csrColumns cursor fast_forward for
    select TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME
        from INFORMATION_SCHEMA.COLUMNS
        where IS_NULLABLE = 'YES'

declare @TABLE_SCHEMA sysname,
        @TABLE_NAME sysname,
        @COLUMN_NAME sysname,
        @sql nvarchar(max)

open csrColumns

while (1=1) begin
    fetch next
        from csrColumns
        into @TABLE_SCHEMA, @TABLE_NAME, @COLUMN_NAME

    if @@FETCH_STATUS<>0 break

    set @sql = N'if not exists(select 1 from ' + QUOTENAME(@TABLE_SCHEMA) + N'.' + QUOTENAME(@TABLE_NAME) + N' where ' + QUOTENAME(@COLUMN_NAME) + N'is not null)
                     insert into #SuspectColumns values (''' + @TABLE_SCHEMA + N''',''' + @TABLE_NAME + N''',''' + @COLUMN_NAME + N''')'

    exec sp_executesql @sql
end /* while */

close csrColumns
deallocate csrColumns

select * from #SuspectColumns

drop table #SuspectColumns