Yes, the second card will cause a chain reaction.
In a case like this you would have three total outbreaks happen. First one from the first card drawn, Baghdad. Then two more from the second card drawn, Tehran.
Flip over as many Infection cards from the top of the Infection Deck as the
current infection rate. This number is below the space of the Infection Rate
Track that has the infection rate marker. Flip these cards over one at a time,
infecting the city named on each card.
To infect a city, place 1 disease cube matching its color onto the city, unless
this disease has been eradicated. If the city already has 3 cubes of this color,
do not place a 4th cube. Instead, an outbreak of this disease occurs in the city
(see Outbreaks below). Discard this card to the Infection Discard Pile.
When a disease outbreak occurs, move the outbreaks marker forward
1 space on the Outbreaks Track. Then, place 1 cube of the disease color
on every city connected to the city. If any of them already has 3 cubes of
the disease color, do not place a 4th cube in those cities. Instead, in each of
them, a chain reaction outbreak occurs after the current outbreak is done.
When a chain reaction outbreak occurs, first move the outbreaks marker
forward 1 space. Then, place cubes as above, except do not add a cube to
cities that have already had an outbreak (or a chain reaction outbreak) as
part of resolving the current Infection card.
As a result of outbreaks, a city may have disease cubes of multiple colors on
it; up to 3 cubes of each color. This does not affect infections.
If you read the outbreaks section closely it only talks about not adding cubes to cities that have already had an outbreak for the current infection card only. So for the situation that you are dealing with there will be an outbreak for each infection card.