Hi @jagrutiwani0, this error is because you are comparing two different data types. Even the value is same here the data type is different.
So while storing the collection variable you can store using JSON.stringify() method,
else you can convert it to integer like this post.
pm.expect(jsonArrayData[0].fields.externalid).to.eql(parseInt(pm.collectionVariables.get("Customer_Number_Netsuite")));
Please try and let me know if this works 