AltSoftSerial is much more reliable than SoftwareSerial, but you have to use two specific pins: 8&9 on a Nano. It disables PWM on pin 10.
My NeoSWSerial is almost as good, and it will work on any two pins. It only supports baud rates 9600, 19200 and 38400.
Both of these libraries are available from the Arduino Library Manager, under the menu Sketch-> Include Library-> Manage Libraries.
SoftwareSerial is very inefficient, because it disables interrupts for long periods of time. It cannot send and receive at the same time.