If you use the linux, you can use "ps -aux" command to file the pid of the browser or any program work in that moment,
then you can use the command "netstat -apn" to chek the ESTABLISHED number of specified PID.
Of course, windows can check the chunks, too.
But, you must use the command - tasklist to check the running programs' PID and use the command - netstat -aon or only -o to chek the ESTABLISHED numbers of the specified PID.
for example,
I use the EasyScript to upload the files to mega and set the chunk numbers = 4 into the python script.
Yes, the script is right, the chunk number is indeed four.
btw, people also can control the upload chunk number by the "transfer settings" of the background control pannel of your mega account.