Statement:
The level of criminal activities is lower in Sri Lanka than in Nigeria

In the The Most Criminal Countries rating Sri Lanka holds position #86 2022 out of 139 and Nigeria is #17 out of 139 2022.
Position of Sri Lanka is better than position of Nigeria.
Nigeria is leader of the "The Most Criminal Countries" rating. So it is wise to avoid visiting the country or, at least, you need to take additional actions to protect your life and belongings, compared to Sri Lanka

Referencies:

  1. The Most Criminal Countries 2022 by Numbeo
    The countries in the rating sorted by 'Crime Index' in descending order.
    Nigeria 'Crime Index' value is 64.09
    Sri Lanka 'Crime Index' value is 40.97