Items displayed in Search suggestions are set from Magento based on their attribute settings. 

  1. Goto Manage Attributes 
  2. Search for the attribute that you want to enable for Search Suggestions 
  3. Make sure it is Enabled as "Yes" for used in Quick Search and also for Layered Navigation (Filterable with results). 
  4. Wait for the Configuration synch to be completed in the next 24 hours or Manually run the configuration synch from the Tagalys Configuration in your Magento Admin, the Tagalys > Configuration > Trouble Shooting