@spubud: Please try heading to Settings > Apps > Snapchat > Notifications > Notification categories > Select a category > Sound > Check the top of the list for an option such as 'App specific sound', or something similar.
If you can't see this option then please head to Settings > Apps > Tap the 3 dots in the top right > Reset app preferences, then try the steps above once again.
If you can't see 'Notification categories' then please head to Settings > Notifications > Advanced settings > Manage notification categories for each app > On.
