I think next Direct will be in end April / early May. Nintendo has not announced any games for August and September. And I do not think they will wait until E3.
Well you are wrong, Mario + Rabbids Kingdom Battle was announced at E3 last year and released in August, Nintendo very often announcing games for Switch only 2-3 months before launch. With that on mind and fact that E3 is in less than 2 months, there is no need for onother Direct before E3, saying that maybe we could get one but higher chances are for something like Mini Direct or some kind specifik Direct like Pokemon Direct.