I prefer a board with 'gadgets' like 7 segment displays, switches and buttons. There is nothing wrong with the DE-10 Nano as long as you have a way to implement the gadgets.
My favorite board at the moment is the Nexys 4 DDR but it is really pricey and probably a bit of overkill:
http://store.digilentinc.com/nexys-4-ddr-artix-7-fpga-trainer-board-recommended-for-ece-curriculum/As a fallback, I would consider the Basys 3 Artix 7 board which is a little more reasonable:
http://store.digilentinc.com/basys-3-artix-7-fpga-trainer-board-recommended-for-introductory-users/These are personal choices, but they are based on the 'gadgets'.
You will need to pick a language to start your travels. You have a choice of 3: VHDL, Verilog (about which I know little) or System Verilog (about which I know nothing). I started with and continue to use VHDL. And, yes, you can start a language war by trying to discuss 'which is better'. Pick one - just make sure it is VHDL.
You need to install the appropriate toolchain: Xilinx Vivado for either of the Digilent boards and Altera <whatever> for the Nano. These will be huge installs and CPU speed WILL matter as soon as you try to synthesize a project.
Books:
"Real World FPGA Design with Verilog" - I really need to read this book. I have it but I haven't had time.
"Digital Design and Computer Architecture" Harris and Harris - Uses System Verilog and VHDL in parallel. You can compare the languages as you go. This book builds a MIPS type CPU from scratch and presents all of the design considerations and their implementation.
"Digital Design and Computer Architecture ARM Edition" Harris and Harris - same authors building an ARM processor.
"Computer Architecture and Design" Patterson and Hennessy - has nothing to do with FPGAs but is considered the gold standard for design. The authors designed the MIPS processors and started the MIPS company.
"RTL Hardware Design Using VHDL" Pong Chu - dedicated to using VHDL properly.
"Introduction to Computing Systems: From Bits and Gates to C and Beyond" Patt and Patel - this book starts at the very beginning of logic design and works up through a RISC CPU and on to an assembler and C compiler. This is a great starter project and is used in many universities. Google for 'LC-3' The book does not present the VHDL but it is a pretty easy project to build as they give you the hardware layout and a description of the state machine. I really like this project! You should definitely have this book!
https://www.amazon.com/Introduction-Computing-Systems-Gates-Beyond/dp/0072467509There are only a very few constructs you need to learn. Gates, registers, multiplexers and finite state machines (unless I forgot a couple). Once you know how to implement these constructs, the rest is just details.
Hint: As you build LC-3, you will see why I want my boards to have 'gadgets'. It sometimes comes to pass that my code isn't perfect right out of the gate. Debugging is easier with 'gadgets'.