You would need to activate the module from Appearance >Nevo Options > Sticky sidebar.
You can find the Sidebars option in the theme Customizer on Appearance → Customize → General → Global Sidebar.
Sticky Sidebar Settings
Sticky Sidebar is only available on Desktop view.
- Sticky on: Sidebar left or Sidebar right or Sidebar left + Sidebar right.
- Ancho: stick on top or stick on bottom.
- Top spacing: distance when sticking above.
- Bottom spacing: distance when sticking below.