A good suggestion! This is currently included in the MODIS 'develop' branch, and it will definitely be part of future package versions (starting with 1.1.4). Until the next CRAN release, simply install the current 'develop' version from GitHub and see if this works for you:
# devtools::install_github("MatMatt/MODIS", ref = "develop")
library(MODIS)
## set point coordinates (taken from https://en.wikipedia.org/wiki/Frankfurt)
dat = data.frame(lon = 8.682222, lat = 50.110556, loc = "Frankfurt am Main")
pts = sf::st_as_sf(dat, coords = c("lon", "lat"), crs = 4326)
## get overlying tile
tls = getTile(pts)
tls@tile
# [1] "h18v03"
One important caveat, though: at the moment, this only works with sp (ie. Spatial*
) and sf point inputs.