Can repro in stable 
Google Chrome	62.0.3202.75 (Official Build) (64-bit) (cohort: 62_75_win)

Verified in stable and canary versions noted above with NVDA 17.3. 

There are two buttons here. First is the button to open the file. This button is labelled with the filename. Pressing applications key will bring up the options menu. The unlabeled button is the control that also brings up this menu.
I would expect the first button to be labelled something like 'open <filename>' and not indicate the sub menu and the second to be labelled 'more options' and sub menu to be indicated here.

Further detail on the two comments here. Visually, the sub-menu (second) button is located inside the first button. From the screen reader perspective, they are two different buttons.  

 Issue 779299  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/49074912451707d0f0e935934f70174cc21490a4

commit 49074912451707d0f0e935934f70174cc21490a4
Author: Aaron Leventhal <aleventhal@chromium.org>
Date: Fri Feb 16 02:36:04 2018

Fix missing accessibility names in browser UI

Address a collection of missing a11y names in browser UI found by
iterating through views in the primary UI and checking for non-empty
accessible names where the view is focusable.

The browser view itself intentionally has no name, so it uses the
explicitly empty name attribute flag.

The textfield control has been updated so that SetAssociatedLabel
can be used to automatically set the name. When this is used the
accessibility labelledby relationship is also automatically set.

Bug:  781485 
Change-Id: Ie6359af94938156ae2ee7f36b73059fe2830cbdc
Reviewed-on: https://chromium-review.googlesource.com/905592
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537121}
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/app/generated_resources.grd
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/apps/guest_view/web_view_browsertest.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/ash/launcher/chrome_launcher_controller.h
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/global_error/global_error_service_browsertest.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/javascript_dialogs/javascript_dialog_browsertest.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/toolbar/toolbar_action_view_controller.h
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/apps/app_info_dialog/app_info_summary_panel.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/cookie_info_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/download/download_item_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/location_bar/find_bar_icon.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/location_bar/icon_label_bubble_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/profiles/avatar_button.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/tab_icon_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/chrome/browser/ui/views/toolbar/toolbar_action_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/accessibility/ax_node_data.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/accessibility/ax_node_data.h
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/views/controls/message_box_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/views/controls/table/table_view.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/views/controls/textfield/textfield.cc
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/views/controls/textfield/textfield.h
[modify] https://crrev.com/49074912451707d0f0e935934f70174cc21490a4/ui/views/controls/webview/webview.cc

There were actually about a dozen nameless fixes in that CL.

Chrome: 66.0.3355.0
NVDA: 2017.4

The options button is now labelled, thank you!
The button labelled with the filename still reports as a submenu, but when activated, opens the file.