I am a 23 male, 65 kg. Is it safe to take supplements like Iso 100, whey protein or Nitro Tech for weight gain?

Probably safe. Protein powders & shakes are not regulated by the USDA; there is no guarantee regarding strength/purity/safety. Independent analyses find the contents to differ from the label. Food sources of protein & calories are preferable. Of course, some allergies exist to whey & other components. If you are not allergic and avoid supplements with unnecessary additives/herbs, should be ok in moderation.