Creamy Cannelloni With Chicken And Almonds

• 22 precooked cannelloni (dried)
• 2 tomatoes (chopped)
• 1 onion (chopped)
• 1 egg
• 350 ml chicken stock
• 210 gr chicken (diced cooked)
• 90 gr swiss cheese (grated)
• 90 gr ricotta cheese
• 45 gr butter
• 40 gr slivered almonds (toasted)