-First, Nintendo is launching Online in second half of September, that means they need to talk about it in first half of September.
-Second, Nintendo with Switch usualy have Direct at around 3 months (I don't count specific Nindies Directs), in June we had E3 Direct so next regular Direct would need to be around September with focus on Q4 lineup. So I suspect we will have one Direct where the will have games and Switch online.
-Third, last year after E3 Direct we had Nindies Direct on August 30. and than regular Direct on September 13., this year we had Nindies Direct on August 28. and my guess would be regular Direct will be somewhere 11-13. September, thats if we don't have it week earlier (04-06. September).
In 2 weeks we will know if I am right. :)