A roundup of the 3.5 years of speculation regarding a new Monster Hunter title coming to Nintendo Switch:
March 2017: Nintendo Switch launched. Nintendo revealed that it increased the amount of memory in the Switch hardware in order for it to be able to run Capcom's RE Engine, which debuted that year on PS4/XB1/PC in RE7. https://www.technobuffalo.com/nintendo-switch-capcom-system-memory
In May 2017, Capcom announced a Switch port of MHXX (Generations Ultimate) for Japan releasing in August, alongside a hardware bundle, which IIRC is the first custom Switch. MHXX originally came out on 3DS on 3/17 (after Switch launched!) https://www.gematsu.com/2017/05/monster-hunter-xx-nintendo-switch-ver-launches-august-25-japan-debut-trailer
In May 2018, 9 months after hitting Japan, Capcom announces Generations Ultimate for the West, and only on Switch (not 3DS). It launches almost exactly a year after the Japanese version. https://nintendoeverything.com/monster-hunter-xx-switch-coming-west-as-monster-hunter-generations-ultimate/
In June 2018, Capcom held a shareholder meeting; an attendee tweeted about it. A shareholder asked if MH World will come to Switch, which Capcom denied. However, without going into detail, the attendee deduced that Capcom had other plans for MH on Switch. https://twitter.com/cvxfreak/status/1011531557729759234?s=20
In March 2019, Capcom celebrated the MH 15th Anniversary. One series director, Ichinose, drew a commemorative card that apparently had the hidden message "NEXT" in it, an apparent hint for a future MH. He did something similar for the 10th anniversary too https://twitter.com/aevanko/status/1105460643774099457
At the June 2020 Capcom shareholder MTG, an attendee again asked about MHW on Switch; Capcom denied it. However, it said it was "planning to develop a [MH] that middle and high-school students can enjoy."
(In JP, PS4 doesn't appeal to this demographic) https://www.gematsu.com/2020/06/capcom-planning-a-monster-hunter-that-middle-and-high-school-students-can-enjoy
(In JP, PS4 doesn't appeal to this demographic) https://www.gematsu.com/2020/06/capcom-planning-a-monster-hunter-that-middle-and-high-school-students-can-enjoy
In Sept 2020, Capcom announced Iceborne's "Final Stand," its last DLC. Any new MH would likely come out after support for Iceborne is finished, and the timing of the announcement preceded Tokyo Game Show 2020. https://www.eurogamer.net/articles/2020-09-01-monster-hunter-world-icebornes-final-update-adds-legendary-black-dragon-fatalis
Monster Hunter has remarkably been shown at TGS every year since 2010. Could 2020 break that streak?
Finally, there's Capcom's "TGS LIVE 2020 SALE" for Japan, in which MH Generations Ultimate on Switch is the most prominently advertised title. Despite 3DS being discontinued at this point, MH3G, MH4G, MHXX, Stories and Poka Poka Airu DX on sale as well. https://www.capcom.co.jp/sale/sale02-ndfPs/
Of course, most of this is speculation, guess work and hearsay. Capcom itself has only ever said that a middle/high-schooler-targeted MH is being planned. A new MH may hit Switch someday, or it may not. Either way, based on the latest rumors, we're about to find out.